Function iViz
has 760 lines of code (exceeds 25 allowed). Consider refactoring. Open
window.iViz = (function(_, $, cbio, QueryByGeneUtil, QueryByGeneTextArea) {
var data_;
var vm_;
var tableData_ = [];
var groupFiltersMap_ = {};
File main.js
has 767 lines of code (exceeds 250 allowed). Consider refactoring. Open
'use strict';
window.iViz = (function(_, $, cbio, QueryByGeneUtil, QueryByGeneTextArea) {
var data_;
var vm_;
var tableData_ = [];
Function iViz
has a Cognitive Complexity of 79 (exceeds 5 allowed). Consider refactoring. Open
window.iViz = (function(_, $, cbio, QueryByGeneUtil, QueryByGeneTextArea) {
var data_;
var vm_;
var tableData_ = [];
var groupFiltersMap_ = {};
- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Function init
has 98 lines of code (exceeds 25 allowed). Consider refactoring. Open
init: function(_rawDataJSON, configs,_selectableIds) {
vm_ = iViz.vue.manage.getInstance();
var selectableIdsSet = {}
_.each(_selectableIds, function(id){
selectableIdsSet[id] = true;
Function extractCnaData
has 67 lines of code (exceeds 25 allowed). Consider refactoring. Open
extractCnaData: function(_cnaData, _allSamples) {
var _cnaMeta = {};
var _allCNAGenes = {};
var _cnaMetaIndex = 0;
var self = this;
Function updateDataObject
has 67 lines of code (exceeds 25 allowed). Consider refactoring. Open
updateDataObject: function(type, attrIds) {
var def = new $.Deferred();
var self_ = this;
var isPatientAttributes = (type === 'patient');
var _data = isPatientAttributes ? data_.groups.patient.data : data_.groups.sample.data;
Function stat
has 66 lines of code (exceeds 25 allowed). Consider refactoring. Open
stat: function() {
var _result = {};
_result.origin = window.cohortIdsList;
_result.filters = {};
var self = this;
Function downloadCaseData
has 53 lines of code (exceeds 25 allowed). Consider refactoring. Open
downloadCaseData: function() {
var _def = new $.Deferred();
var sampleUIds_ = vm_.selectedsampleUIDs;
var attr = {};
var self = this;
Function extractMutationData
has 48 lines of code (exceeds 25 allowed). Consider refactoring. Open
extractMutationData: function(_mutationData, _allSamples) {
var _mutGeneMeta = {};
var _allMutGenes = _.pluck(_mutationData, 'gene_symbol');
var _mutGeneMetaIndex = 0;
var self = this;
Function openCases
has 39 lines of code (exceeds 25 allowed). Consider refactoring. Open
openCases: function() {
var _selectedCasesMap = {};
var _patientData = data_.groups.patient.data;
$.each(vm_.selectedpatientUIDs, function(key, patientUID) {
var _caseDataObj = _patientData[patientUID];
Function getDataWithAttrs
has 38 lines of code (exceeds 25 allowed). Consider refactoring. Open
getDataWithAttrs: function(type, attrIds) {
var def = new $.Deferred();
var isPatientAttributes = (type === 'patient');
var hasAttrDataMap = isPatientAttributes ? data_.groups.patient.has_attr_data : data_.groups.sample.has_attr_data;
var attrDataToGet = [];
Function getNavCaseIdsStr
has 32 lines of code (exceeds 25 allowed). Consider refactoring. Open
function getNavCaseIdsStr(selectedCasesMap, selectedCaseIds, underURLLimit) {
var result = {
str: '',
limit: -1
};
Function iViz
has 5 arguments (exceeds 4 allowed). Consider refactoring. Open
window.iViz = (function(_, $, cbio, QueryByGeneUtil, QueryByGeneTextArea) {
'iViz' is not defined. Open
vm_ = iViz.vue.manage.getInstance();
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iviz' is not defined. Open
_.each(iviz.datamanager.sortByNumOfStudies(
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
if (chartsCount < iViz.opts.numOfChartsLimit) {
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
content.case_uids = iViz.util.unique(content.case_ids);
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
$.when(iViz.getDataWithAttrs(_type, _attrIds))
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
content.case_uids = iViz.util.unique(content.case_ids);
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'_attrIds' is already defined Open
var _attrIds = [_caseAttrId, 'study_id'];
- Read upRead up
- Exclude checks
Disallow Redeclaring Variables (no-redeclare)
In JavaScript, it's possible to redeclare the same variable name using var
. This can lead to confusion as to where the variable is actually declared and initialized.
Rule Details
This rule is aimed at eliminating variables that have multiple declarations in the same scope.
Examples of incorrect code for this rule:
/*eslint no-redeclare: "error"*/
var a = 3;
var a = 10;
Examples of correct code for this rule:
/*eslint no-redeclare: "error"*/
var a = 3;
// ...
a = 10;
Options
This rule takes one optional argument, an object with a boolean property "builtinGlobals"
. It defaults to false
.
If set to true
, this rule also checks redeclaration of built-in globals, such as Object
, Array
, Number
...
builtinGlobals
Examples of incorrect code for the { "builtinGlobals": true }
option:
/*eslint no-redeclare: ["error", { "builtinGlobals": true }]*/
var Object = 0;
Examples of incorrect code for the { "builtinGlobals": true }
option and the browser
environment:
/*eslint no-redeclare: ["error", { "builtinGlobals": true }]*/
/*eslint-env browser*/
var top = 0;
The browser
environment has many built-in global variables (for example, top
). Some of built-in global variables cannot be redeclared.
Source: http://eslint.org/docs/rules/
'iViz' is not defined. Open
$.when(iViz.getDataWithAttrs(group.type, _attrIds)).then(function(selectedData_) {
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
$.when(iViz.getDataWithAttrs(groupNdxData_.type, attrIds)).then(function(selectedData_) {
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'limit' is already defined Open
var limit = limit > 50 ?
- Read upRead up
- Exclude checks
Disallow Redeclaring Variables (no-redeclare)
In JavaScript, it's possible to redeclare the same variable name using var
. This can lead to confusion as to where the variable is actually declared and initialized.
Rule Details
This rule is aimed at eliminating variables that have multiple declarations in the same scope.
Examples of incorrect code for this rule:
/*eslint no-redeclare: "error"*/
var a = 3;
var a = 10;
Examples of correct code for this rule:
/*eslint no-redeclare: "error"*/
var a = 3;
// ...
a = 10;
Options
This rule takes one optional argument, an object with a boolean property "builtinGlobals"
. It defaults to false
.
If set to true
, this rule also checks redeclaration of built-in globals, such as Object
, Array
, Number
...
builtinGlobals
Examples of incorrect code for the { "builtinGlobals": true }
option:
/*eslint no-redeclare: ["error", { "builtinGlobals": true }]*/
var Object = 0;
Examples of incorrect code for the { "builtinGlobals": true }
option and the browser
environment:
/*eslint no-redeclare: ["error", { "builtinGlobals": true }]*/
/*eslint-env browser*/
var top = 0;
The browser
environment has many built-in global variables (for example, top
). Some of built-in global variables cannot be redeclared.
Source: http://eslint.org/docs/rules/
'iViz' is not defined. Open
strA = iViz.util.getAttrVal(attr, arr[i]);
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
numOfKeys > iViz.opts.pie2TableLimit) {
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
iViz.init(data_, _selectedSamples, _selectedPatients);
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
iViz.vue.manage.getInstance().increaseStudyViewSummaryPagePBStatus();
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
'iViz' is not defined. Open
updatedAttrIds = iViz.util.unique(updatedAttrIds);
- Read upRead up
- Exclude checks
Disallow Undeclared Variables (no-undef)
This rule can help you locate potential ReferenceErrors resulting from misspellings of variable and parameter names, or accidental implicit globals (for example, from forgetting the var
keyword in a for
loop initializer).
Rule Details
Any reference to an undeclared variable causes a warning, unless the variable is explicitly mentioned in a /*global ...*/
comment.
Examples of incorrect code for this rule:
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
Examples of correct code for this rule with global
declaration:
/*global someFunction b:true*/
/*eslint no-undef: "error"*/
var a = someFunction();
b = 10;
The b:true
syntax in /*global */
indicates that assignment to b
is correct.
Examples of incorrect code for this rule with global
declaration:
/*global b*/
/*eslint no-undef: "error"*/
b = 10;
By default, variables declared in /*global */
are read-only, therefore assignment is incorrect.
Options
-
typeof
set to true will warn for variables used inside typeof check (Default false).
typeof
Examples of correct code for the default { "typeof": false }
option:
/*eslint no-undef: "error"*/
if (typeof UndefinedIdentifier === "undefined") {
// do something ...
}
You can use this option if you want to prevent typeof
check on a variable which has not been declared.
Examples of incorrect code for the { "typeof": true }
option:
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Examples of correct code for the { "typeof": true }
option with global
declaration:
/*global a*/
/*eslint no-undef: ["error", { "typeof": true }] */
if(typeof a === "string"){}
Environments
For convenience, ESLint provides shortcuts that pre-define global variables exposed by popular libraries and runtime environments. This rule supports these environments, as listed in Specifying Environments. A few examples are given below.
browser
Examples of correct code for this rule with browser
environment:
/*eslint no-undef: "error"*/
/*eslint-env browser*/
setTimeout(function() {
alert("Hello");
});
node
Examples of correct code for this rule with node
environment:
/*eslint no-undef: "error"*/
/*eslint-env node*/
var fs = require("fs");
module.exports = function() {
console.log(fs);
};
When Not To Use It
If explicit declaration of global variables is not to your taste.
Compatibility
This rule provides compatibility with treatment of global variables in JSHint and JSLint.
Further Reading
Unexpected 'else' after 'return'. Open
} else {
- Read upRead up
- Exclude checks
Disallow return before else (no-else-return)
If an if
block contains a return
statement, the else
block becomes unnecessary. Its contents can be placed outside of the block.
function foo() {
if (x) {
return y;
} else {
return z;
}
}
Rule Details
This rule is aimed at highlighting an unnecessary block of code following an if
containing a return statement. As such, it will warn when it encounters an else
following a chain of if
s, all of them containing a return
statement.
Examples of incorrect code for this rule:
/*eslint no-else-return: "error"*/
function foo() {
if (x) {
return y;
} else {
return z;
}
}
function foo() {
if (x) {
return y;
} else if (z) {
return w;
} else {
return t;
}
}
function foo() {
if (x) {
return y;
} else {
var t = "foo";
}
return t;
}
// Two warnings for nested occurrences
function foo() {
if (x) {
if (y) {
return y;
} else {
return x;
}
} else {
return z;
}
}
Examples of correct code for this rule:
/*eslint no-else-return: "error"*/
function foo() {
if (x) {
return y;
}
return z;
}
function foo() {
if (x) {
return y;
} else if (z) {
var t = "foo";
} else {
return w;
}
}
function foo() {
if (x) {
if (z) {
return y;
}
} else {
return z;
}
}
Source: http://eslint.org/docs/rules/
Similar blocks of code found in 2 locations. Consider refactoring. Open
if (data_.groups.sample.data[_caseIdIndex].cna_details === undefined) {
data_.groups.sample.data[_caseIdIndex].cna_details = [_cnaMeta[_uniqueId].index];
} else {
data_.groups.sample.data[_caseIdIndex].cna_details.push(_cnaMeta[_uniqueId].index);
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 111.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if (data_.groups.sample.data[_caseUIdIndex].mutated_genes === undefined) {
data_.groups.sample.data[_caseUIdIndex].mutated_genes = [_mutGeneMeta[_uniqueId].index];
} else {
data_.groups.sample.data[_caseUIdIndex].mutated_genes.push(_mutGeneMeta[_uniqueId].index);
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 111.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
} else if (attrId === 'cna_details') {
$.when(window.iviz.datamanager.getCnaData(progressFunc))
.then(function(_data) {
def.resolve(self.extractCnaData(_data, window.iviz.datamanager.getAllCNASamples()));
}, function() {
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 96.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if (attrId === 'mutated_genes') {
$.when(window.iviz.datamanager.getMutData(progressFunc))
.then(function(_data) {
def.resolve(self.extractMutationData(_data, window.iviz.datamanager.getAllMutatedGeneSamples()));
}, function() {
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 96.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if (data_.groups.sample.data[_caseIdIndex].cna_details === undefined) {
data_.groups.sample.data[_caseIdIndex].cna_details = [_cnaMetaIndex];
} else {
data_.groups.sample.data[_caseIdIndex].cna_details.push(_cnaMetaIndex);
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 95.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if (data_.groups.sample.data[_caseUIdIndex].mutated_genes === undefined) {
data_.groups.sample.data[_caseUIdIndex].mutated_genes = [_mutGeneMetaIndex];
} else {
data_.groups.sample.data[_caseUIdIndex].mutated_genes.push(_mutGeneMetaIndex);
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 95.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
groups.push({
type: 'patient',
id: vm_.groupCount.toString(),
selectedcases: [],
hasfilters: false,
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 89.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
groups.push({
type: 'sample',
id: vm_.groupCount.toString(),
selectedcases: [],
hasfilters: false,
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 89.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(_allSamples, function(samples, studyId) {
_.each(samples, function(sampleId) {
tableData_.cna_details.allSamples.push({
"molecularProfileId": window.iviz.datamanager.getCNAProfileIdByStudyId(studyId),
"sampleId": sampleId
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 83.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(_allSamples, function(samples, studyId) {
_.each(samples, function(sampleId) {
tableData_.mutated_genes.allSamples.push({
"molecularProfileId": window.iviz.datamanager.getMutationProfileIdByStudyId(studyId),
"sampleId": sampleId
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 83.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(patientAttr_, function(_attr) {
if (attr[_attr.attr_id] === undefined &&
_attr.view_type !== 'survival') {
attr[_attr.attr_id] = _attr.display_name;
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 68.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(sampleAttr_, function(_attr) {
if (attr[_attr.attr_id] === undefined &&
_attr.view_type !== 'scatter_plot') {
attr[_attr.attr_id] = _attr.display_name;
}
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 68.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(_.pluck(_vc.studies, 'patients'), function(_arr) {
_selectedPatients = _selectedPatients.concat(_arr);
});
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 46.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
_.each(_.pluck(_vc.studies, 'samples'), function(_arr) {
_selectedSamples = _selectedSamples.concat(_arr);
});
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 46.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 4 locations. Consider refactoring. Open
_.each(_cnaMeta, function(content) {
content.case_uids = iViz.util.unique(content.case_ids);
});
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 45.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 4 locations. Consider refactoring. Open
_.each(_mutGeneMeta, function(content) {
content.case_uids = iViz.util.unique(content.case_ids);
});
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 45.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Expected indentation of 6 space characters but found 8. Open
});
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Expected space or tab after '//' in comment. Open
//Show unknown samples error message, whenthe initial(pie and bar) charts are loaded
- Read upRead up
- Exclude checks
Requires or disallows a whitespace (space or tab) beginning a comment (spaced-comment)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Some style guides require or disallow a whitespace immediately after the initial //
or /*
of a comment.
Whitespace after the //
or /*
makes it easier to read text in comments.
On the other hand, commenting out code is easier without having to put a whitespace right after the //
or /*
.
Rule Details
This rule will enforce consistency of spacing after the start of a comment //
or /*
. It also provides several
exceptions for various documentation styles.
Options
The rule takes two options.
-
The first is a string which be either
"always"
or"never"
. The default is"always"
.- If
"always"
then the//
or/*
must be followed by at least one whitespace. - If
"never"
then there should be no whitespace following.
- If
-
This rule can also take a 2nd option, an object with either of the following keys:
"exceptions"
and"markers"
.- The
"exceptions"
value is an array of string patterns which are considered exceptions to the rule. Please note that exceptions are ignored if the first argument is"never"
.
"spaced-comment": ["error", "always", { "exceptions": ["-", "+"] }]
- The
"markers"
value is an array of string patterns which are considered markers for docblock-style comments, such as an additional/
, used to denote documentation read by doxygen, vsdoc, etc. which must have additional characters. The"markers"
array will apply regardless of the value of the first argument, e.g."always"
or"never"
.
"spaced-comment": ["error", "always", { "markers": ["/"] }]
- The
The difference between a marker and an exception is that a marker only appears at the beginning of the comment whereas exceptions can occur anywhere in the comment string.
You can also define separate exceptions and markers for block and line comments:
"spaced-comment": ["error", "always", {
"line": {
"markers": ["/"],
"exceptions": ["-", "+"]
},
"block": {
"markers": ["!"],
"exceptions": ["*"]
}
}]
always
The following patterns are considered problems:
/*eslint spaced-comment: ["error", "always"]*/
//This is a comment with no whitespace at the beginning
/*This is a comment with no whitespace at the beginning */
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always"] */
// This is a comment with a whitespace at the beginning
/* This is a comment with a whitespace at the beginning */
/*
* This is a comment with a whitespace at the beginning
*/
/*
This comment has a newline
*/
/* eslint spaced-comment: ["error", "always"] */
/**
* I am jsdoc
*/
never
The following patterns are considered problems:
/*eslint spaced-comment: ["error", "never"]*/
// This is a comment with a whitespace at the beginning
/* This is a comment with a whitespace at the beginning */
/* \nThis is a comment with a whitespace at the beginning */
The following patterns are not considered problems:
/*eslint spaced-comment: ["error", "never"]*/
/*This is a comment with no whitespace at the beginning */
/*eslint spaced-comment: ["error", "never"]*/
/**
* I am jsdoc
*/
exceptions
The following patterns are considered problems:
/* eslint spaced-comment: ["error", "always", { "block": { "exceptions": ["-"] } }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-", "+"] }] */
//------++++++++
// Comment block
//------++++++++
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-", "+"] }] */
/*------++++++++*/
/* Comment block */
/*------++++++++*/
/* eslint spaced-comment: ["error", "always", { "line": { "exceptions": ["-+"] } }] */
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-"] }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "line": { "exceptions": ["-"] } }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "exceptions": ["*"] }] */
/****************
* Comment block
****************/
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-+"] }] */
//-+-+-+-+-+-+-+
// Comment block
//-+-+-+-+-+-+-+
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
/* eslint spaced-comment: ["error", "always", { "block": { "exceptions": ["-+"] } }] */
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
markers
The following patterns are considered problems:
/* eslint spaced-comment: ["error", "always", { "markers": ["/"] }] */
///This is a comment with a marker but without whitespace
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always", { "markers": ["/"] }] */
/// This is a comment with a marker
/*eslint spaced-comment: ["error", "never", { "markers": ["!<"] }]*/
//!<this is a line comment with marker block subsequent lines are ignored></this>
/* eslint spaced-comment: ["error", "always", { "markers": ["global"] }] */
/*global ABC*/
Related Rules
- [spaced-line-comment](spaced-line-comment.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
var str = ''
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
str = str+'<br/>'+obj.studyId+':'+sample
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Missing semicolon. Open
var selectableIdsSet = {}
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 176 exceeds the maximum line length of 80. Open
vm_.selectedsampleUIDs = _.pluck(data_.groups.sample.data, 'sample_uid');
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 177 exceeds the maximum line length of 80. Open
vm_.selectedpatientUIDs = _.pluck(data_.groups.patient.data, 'patient_uid');
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
str = str+'<br/>'+obj.studyId+':'+sample
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
str = str+'<br/>'+obj.studyId+':'+sample
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Missing space before opening brace. Open
_.each(_selectableIds, function(id){
- Read upRead up
- Exclude checks
Require Or Disallow Space Before Blocks (space-before-blocks)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Consistency is an important part of any style guide. While it is a personal preference where to put the opening brace of blocks, it should be consistent across a whole project. Having an inconsistent style distracts the reader from seeing the important parts of the code.
Rule Details
This rule will enforce consistency of spacing before blocks. It is only applied on blocks that don’t begin on a new line.
- This rule ignores spacing which is between
=>
and a block. The spacing is handled by thearrow-spacing
rule. - This rule ignores spacing which is between a keyword and a block. The spacing is handled by the
keyword-spacing
rule.
Options
This rule takes one argument. If it is "always"
then blocks must always have at least one preceding space. If "never"
then all blocks should never have any preceding space. If different spacing is desired for function
blocks, keyword blocks and classes, an optional configuration object can be passed as the rule argument to
configure the cases separately.
( e.g. { "functions": "never", "keywords": "always", classes: "always" }
)
The default is "always"
.
"always"
The following patterns are considered problems:
/*eslint space-before-blocks: "error"*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try {} catch(a){}
class Foo{
constructor(){}
}
The following patterns are not considered problems:
/*eslint space-before-blocks: "error"*/
if (a) {
b();
}
if (a) {
b();
} else{ /*no error. this is checked by `keyword-spacing` rule.*/
c();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
"never"
The following patterns are considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a) {
b();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
The following patterns are not considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try{} catch(a){}
class Foo{
constructor(){}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
function a() {}
try {} catch(a){}
class Foo{
constructor() {}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
for (;;) {
// ...
}
describe(function(){
// ...
});
class Foo {
constructor(){}
}
The following patterns are considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
function a(){}
try {} catch(a) {}
class Foo {
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
if (a){
b();
}
var a = function() {}
class Foo{
constructor() {}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo{
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo {
constructor(){}
}
When Not To Use It
You can turn this rule off if you are not concerned with the consistency of spacing before blocks or if you are using the space-after-keywords
rule set to "never"
.
Related Rules
- [keyword-spacing](keyword-spacing.md)
- [arrow-spacing](arrow-spacing.md)
- [brace-style](brace-style.md) Source: http://eslint.org/docs/rules/
Expected space(s) after "if". Open
if(selectableIdsSet[cohortIds[i]]){
- Read upRead up
- Exclude checks
enforce consistent spacing before and after keywords (keyword-spacing)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Keywords are syntax elements of JavaScript, such as function
and if
.
These identifiers have special meaning to the language and so often appear in a different color in code editors.
As an important part of the language, style guides often refer to the spacing that should be used around keywords.
For example, you might have a style guide that says keywords should be always surrounded by spaces, which would mean if-else
statements must look like this:
if (foo) {
// ...
} else {
// ...
}
Of course, you could also have a style guide that disallows spaces around keywords.
Rule Details
This rule enforces consistent spacing around keywords and keyword-like tokens: as
(in module declarations), break
, case
, catch
, class
, const
, continue
, debugger
, default
, delete
, do
, else
, export
, extends
, finally
, for
, from
(in module declarations), function
, get
(of getters), if
, import
, in
, instanceof
, let
, new
, of
(in for-of statements), return
, set
(of setters), static
, super
, switch
, this
, throw
, try
, typeof
, var
, void
, while
, with
, and yield
. This rule is designed carefully not to conflict with other spacing rules: it does not apply to spacing where other rules report problems.
Options
This rule has an object option:
-
"before": true
(default) requires at least one space before keywords -
"before": false
disallows spaces before keywords -
"after": true
(default) requires at least one space after keywords -
"after": false
disallows spaces after keywords -
"overrides"
allows overriding spacing style for specified keywords
before
Examples of incorrect code for this rule with the default { "before": true }
option:
/*eslint keyword-spacing: ["error", { "before": true }]*/
if (foo) {
//...
}else if (bar) {
//...
}else {
//...
}
Examples of correct code for this rule with the default { "before": true }
option:
/*eslint keyword-spacing: ["error", { "before": true }]*/
/*eslint-env es6*/
if (foo) {
//...
} else if (bar) {
//...
} else {
//...
}
// no conflict with `array-bracket-spacing`
let a = [this];
let b = [function() {}];
// no conflict with `arrow-spacing`
let a = ()=> this.foo;
// no conflict with `block-spacing`
{function foo() {}}
// no conflict with `comma-spacing`
let a = [100,this.foo, this.bar];
// not conflict with `computed-property-spacing`
obj[this.foo] = 0;
// no conflict with `generator-star-spacing`
function *foo() {}
// no conflict with `key-spacing`
let obj = {
foo:function() {}
};
// no conflict with `object-curly-spacing`
let obj = {foo: this};
// no conflict with `semi-spacing`
let a = this;function foo() {}
// no conflict with `space-in-parens`
(function () {})();
// no conflict with `space-infix-ops`
if ("foo"in {foo: 0}) {}
if (10+this.foo<= this.bar) {}
// no conflict with `jsx-curly-spacing`
let a =
Examples of incorrect code for this rule with the { "before": false }
option:
/*eslint keyword-spacing: ["error", { "before": false }]*/
if (foo) {
//...
} else if (bar) {
//...
} else {
//...
}
Examples of correct code for this rule with the { "before": false }
option:
/*eslint keyword-spacing: ["error", { "before": false }]*/
if (foo) {
//...
}else if (bar) {
//...
}else {
//...
}
after
Examples of incorrect code for this rule with the default { "after": true }
option:
/*eslint keyword-spacing: ["error", { "after": true }]*/
if(foo) {
//...
} else if(bar) {
//...
} else{
//...
}
Examples of correct code for this rule with the default { "after": true }
option:
/*eslint keyword-spacing: ["error", { "after": true }]*/
if (foo) {
//...
} else if (bar) {
//...
} else {
//...
}
// not conflict with `array-bracket-spacing`
let a = [this];
// not conflict with `arrow-spacing`
let a = ()=> this.foo;
// not conflict with `comma-spacing`
let a = [100, this.foo, this.bar];
// not conflict with `computed-property-spacing`
obj[this.foo] = 0;
// not conflict with `generator-star-spacing`
function* foo() {}
// not conflict with `key-spacing`
let obj = {
foo:function() {}
};
// not conflict with `no-spaced-func`
class A {
constructor() {
super();
}
}
// not conflict with `object-curly-spacing`
let obj = {foo: this};
// not conflict with `semi-spacing`
let a = this;function foo() {}
// not conflict with `space-before-function-paren`
function() {}
// no conflict with `space-infix-ops`
if ("foo"in{foo: 0}) {}
if (10+this.foo<= this.bar) {}
// no conflict with `space-unary-ops`
function* foo(a) {
return yield+a;
}
// no conflict with `yield-star-spacing`
function* foo(a) {
return yield* a;
}
// no conflict with `jsx-curly-spacing`
let a =
Examples of incorrect code for this rule with the { "after": false }
option:
/*eslint keyword-spacing: ["error", { "after": false }]*/
if (foo) {
//...
} else if (bar) {
//...
} else {
//...
}
Examples of correct code for this rule with the { "after": false }
option:
/*eslint keyword-spacing: ["error", { "after": false }]*/
if(foo) {
//...
} else if(bar) {
//...
} else{
//...
}
overrides
Examples of correct code for this rule with the { "overrides": { "if": { "after": false }, "for": { "after": false }, "while": { "after": false } } }
option:
/*eslint keyword-spacing: ["error", { "overrides": {
"if": { "after": false },
"for": { "after": false },
"while": { "after": false }
} }]*/
if(foo) {
//...
} else if(bar) {
//...
} else {
//...
}
for(;;);
while(true) {
//...
}
When Not To Use It
If you don't want to enforce consistency on keyword spacing, then it's safe to disable this rule. Source: http://eslint.org/docs/rules/
Missing space before opening brace. Open
if(selectableIdsSet[cohortIds[i]]){
- Read upRead up
- Exclude checks
Require Or Disallow Space Before Blocks (space-before-blocks)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Consistency is an important part of any style guide. While it is a personal preference where to put the opening brace of blocks, it should be consistent across a whole project. Having an inconsistent style distracts the reader from seeing the important parts of the code.
Rule Details
This rule will enforce consistency of spacing before blocks. It is only applied on blocks that don’t begin on a new line.
- This rule ignores spacing which is between
=>
and a block. The spacing is handled by thearrow-spacing
rule. - This rule ignores spacing which is between a keyword and a block. The spacing is handled by the
keyword-spacing
rule.
Options
This rule takes one argument. If it is "always"
then blocks must always have at least one preceding space. If "never"
then all blocks should never have any preceding space. If different spacing is desired for function
blocks, keyword blocks and classes, an optional configuration object can be passed as the rule argument to
configure the cases separately.
( e.g. { "functions": "never", "keywords": "always", classes: "always" }
)
The default is "always"
.
"always"
The following patterns are considered problems:
/*eslint space-before-blocks: "error"*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try {} catch(a){}
class Foo{
constructor(){}
}
The following patterns are not considered problems:
/*eslint space-before-blocks: "error"*/
if (a) {
b();
}
if (a) {
b();
} else{ /*no error. this is checked by `keyword-spacing` rule.*/
c();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
"never"
The following patterns are considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a) {
b();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
The following patterns are not considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try{} catch(a){}
class Foo{
constructor(){}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
function a() {}
try {} catch(a){}
class Foo{
constructor() {}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
for (;;) {
// ...
}
describe(function(){
// ...
});
class Foo {
constructor(){}
}
The following patterns are considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
function a(){}
try {} catch(a) {}
class Foo {
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
if (a){
b();
}
var a = function() {}
class Foo{
constructor() {}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo{
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo {
constructor(){}
}
When Not To Use It
You can turn this rule off if you are not concerned with the consistency of spacing before blocks or if you are using the space-after-keywords
rule set to "never"
.
Related Rules
- [keyword-spacing](keyword-spacing.md)
- [arrow-spacing](arrow-spacing.md)
- [brace-style](brace-style.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
str = str+'<br/>'+obj.studyId+':'+sample
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 189 exceeds the maximum line length of 80. Open
new Notification().createNotification('Following sample(s) might have been deleted/updated with the recent data updates<br/>'+str, {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
str = str+'<br/>'+obj.studyId+':'+sample
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
var includeCases= true;
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Strings must use singlequote. Open
targetList.push(studyId + ":" + patientId);
- Read upRead up
- Exclude checks
Enforce Quote Style (quotes)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:
/*eslint-env es6*/
var double = "double";
var single = 'single';
var backtick = `backtick`; // ES6 only
Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).
Many codebases require strings to be defined in a consistent manner.
Rule Details
This rule is aimed at ensuring consistency of string quotes and as such will report a problem when an inconsistent style is found.
The rule configuration takes up to two options:
- The first option is
"double"
,"single"
or"backtick"
for double-quotes, single-quotes or backticks respectively. The default is"double"
. - The second option takes two options:
-
"avoidEscape"
: When using"avoidEscape"
, this rule will not report a problem when a string is using single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise. For example, if you specify"double"
and"avoidEscape"
, the string'He said, "hi!"'
is not considered a problem because using double quotes for that string would require escaping the double quotes inside of the string. This option is off by default. -
"allowTemplateLiterals"
: when using"allowTemplateLiterals"
, this rule will not report a problem when a string is using backticks and option one is either"double"
or"single"
.
-
When using "single"
or "double"
, template literals that don't contain a substitution, don't contain a line break and aren't tagged templates, are flagged as problems, even with the "avoidEscape"
option. However they are not problems when "allowTemplateLiterals"
is used.
Configuration looks like this:
[2, "single", {"avoidEscape": true, "allowTemplateLiterals": true}]
Deprecation notice: The avoid-escape
option is a deprecated syntax and you should use the object form instead.
The following patterns are considered problems:
/*eslint quotes: ["error", "double"]*/
var single = 'single';
var unescaped = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single"]*/
var double = "double";
var unescaped = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var single = 'single';
var double = "double";
The following patterns are not considered problems:
/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/
var double = "double";
var backtick = `back\ntick`; // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag
/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/
var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"allowTemplateLiterals": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"allowTemplateLiterals": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/
var backtick = `backtick`;
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var double = "a string containing `backtick` quotes"
When Not To Use It
If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/
A space is required after ','. Open
init: function(_rawDataJSON, configs,_selectableIds) {
- Read upRead up
- Exclude checks
Enforces spacing around commas (comma-spacing)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Spacing around commas improve readability of a list of items. Although most of the style guidelines for languages prescribe adding a space after a comma and not before it, it is subjective to the preferences of a project.
var foo = 1, bar = 2;
var foo = 1 ,bar = 2;
Rule Details
This rule enforces consistent spacing before and after commas in variable declarations, array literals, object literals, function parameters, and sequences.
This rule does not apply in an ArrayExpression
or ArrayPattern
in either of the following cases:
- adjacent null elements
- an initial null element, to avoid conflicts with the [
array-bracket-spacing
](array-bracket-spacing.md) rule
Options
This rule has an object option:
-
"before": false
(default) disallows spaces before commas -
"before": true
requires one or more spaces before commas -
"after": true
(default) requires one or more spaces after commas -
"after": false
disallows spaces after commas
after
Examples of incorrect code for this rule with the default { "before": false, "after": true }
options:
/*eslint comma-spacing: ["error", { "before": false, "after": true }]*/
var foo = 1 ,bar = 2;
var arr = [1 , 2];
var obj = {"foo": "bar" ,"baz": "qur"};
foo(a ,b);
new Foo(a ,b);
function foo(a ,b){}
a ,b
Examples of correct code for this rule with the default { "before": false, "after": true }
options:
/*eslint comma-spacing: ["error", { "before": false, "after": true }]*/
var foo = 1, bar = 2
, baz = 3;
var arr = [1, 2];
var arr = [1,, 3]
var obj = {"foo": "bar", "baz": "qur"};
foo(a, b);
new Foo(a, b);
function foo(a, b){}
a, b
Example of correct code for this rule with initial null element for the default { "before": false, "after": true }
options:
/*eslint comma-spacing: ["error", { "before": false, "after": true }]*/
/*eslint array-bracket-spacing: ["error", "always"]*/
var arr = [ , 2, 3 ]
before
Examples of incorrect code for this rule with the { "before": true, "after": false }
options:
/*eslint comma-spacing: ["error", { "before": true, "after": false }]*/
var foo = 1, bar = 2;
var arr = [1 , 2];
var obj = {"foo": "bar", "baz": "qur"};
new Foo(a,b);
function foo(a,b){}
a, b
Examples of correct code for this rule with the { "before": true, "after": false }
options:
/*eslint comma-spacing: ["error", { "before": true, "after": false }]*/
var foo = 1 ,bar = 2 ,
baz = true;
var arr = [1 ,2];
var arr = [1 ,,3]
var obj = {"foo": "bar" ,"baz": "qur"};
foo(a ,b);
new Foo(a ,b);
function foo(a ,b){}
a ,b
Examples of correct code for this rule with initial null element for the { "before": true, "after": false }
options:
/*eslint comma-spacing: ["error", { "before": true, "after": false }]*/
/*eslint array-bracket-spacing: ["error", "never"]*/
var arr = [,2 ,3]
When Not To Use It
If your project will not be following a consistent comma-spacing pattern, turn this rule off.
Further Reading
Related Rules
- [array-bracket-spacing](array-bracket-spacing.md)
- [comma-style](comma-style.md)
- [space-in-brackets](space-in-brackets.md) (deprecated)
- [space-in-parens](space-in-parens.md)
- [space-infix-ops](space-infix-ops.md)
- [space-after-keywords](space-after-keywords)
- [space-unary-ops](space-unary-ops)
- [space-return-throw-case](space-return-throw-case) Source: http://eslint.org/docs/rules/
Missing space before opening brace. Open
window.iviz.datamanager.unknownSamples.forEach(function(obj){
- Read upRead up
- Exclude checks
Require Or Disallow Space Before Blocks (space-before-blocks)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Consistency is an important part of any style guide. While it is a personal preference where to put the opening brace of blocks, it should be consistent across a whole project. Having an inconsistent style distracts the reader from seeing the important parts of the code.
Rule Details
This rule will enforce consistency of spacing before blocks. It is only applied on blocks that don’t begin on a new line.
- This rule ignores spacing which is between
=>
and a block. The spacing is handled by thearrow-spacing
rule. - This rule ignores spacing which is between a keyword and a block. The spacing is handled by the
keyword-spacing
rule.
Options
This rule takes one argument. If it is "always"
then blocks must always have at least one preceding space. If "never"
then all blocks should never have any preceding space. If different spacing is desired for function
blocks, keyword blocks and classes, an optional configuration object can be passed as the rule argument to
configure the cases separately.
( e.g. { "functions": "never", "keywords": "always", classes: "always" }
)
The default is "always"
.
"always"
The following patterns are considered problems:
/*eslint space-before-blocks: "error"*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try {} catch(a){}
class Foo{
constructor(){}
}
The following patterns are not considered problems:
/*eslint space-before-blocks: "error"*/
if (a) {
b();
}
if (a) {
b();
} else{ /*no error. this is checked by `keyword-spacing` rule.*/
c();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
"never"
The following patterns are considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a) {
b();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
The following patterns are not considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try{} catch(a){}
class Foo{
constructor(){}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
function a() {}
try {} catch(a){}
class Foo{
constructor() {}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
for (;;) {
// ...
}
describe(function(){
// ...
});
class Foo {
constructor(){}
}
The following patterns are considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
function a(){}
try {} catch(a) {}
class Foo {
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
if (a){
b();
}
var a = function() {}
class Foo{
constructor() {}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo{
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo {
constructor(){}
}
When Not To Use It
You can turn this rule off if you are not concerned with the consistency of spacing before blocks or if you are using the space-after-keywords
rule set to "never"
.
Related Rules
- [keyword-spacing](keyword-spacing.md)
- [arrow-spacing](arrow-spacing.md)
- [brace-style](brace-style.md) Source: http://eslint.org/docs/rules/
Missing JSDoc comment. Open
function getNavCaseIdsStr(selectedCasesMap, selectedCaseIds, underURLLimit) {
- Read upRead up
- Exclude checks
Require JSDoc comment (require-jsdoc)
JSDoc is a JavaScript API documentation generator. It uses specially-formatted comments inside of code to generate API documentation automatically. For example, this is what a JSDoc comment looks like for a function:
/**
* Adds two numbers together.
* @param {int} num1 The first number.
* @param {int} num2 The second number.
* @returns {int} The sum of the two numbers.
*/
function sum(num1, num2) {
return num1 + num2;
}
Some style guides require JSDoc comments for all functions as a way of explaining function behavior.
Rule Details
This rule generates warnings for nodes that do not have JSDoc comments when they should. Supported nodes:
FunctionDeclaration
ClassDeclaration
MethodDefinition
Options
This rule accepts a require
object with its properties as
-
FunctionDeclaration
(default:true
) -
ClassDeclaration
(default:false
) -
MethodDefinition
(default:false
)
Default option settings are
{
"require-jsdoc": ["error", {
"require": {
"FunctionDeclaration": true,
"MethodDefinition": false,
"ClassDeclaration": false
}
}]
}
The following patterns are considered problems:
/*eslint "require-jsdoc": ["error", {
"require": {
"FunctionDeclaration": true,
"MethodDefinition": true,
"ClassDeclaration": true
}
}]*/
function foo() {
return 10;
}
class Test{
getDate(){}
}
The following patterns are not considered problems:
/*eslint "require-jsdoc": ["error", {
"require": {
"FunctionDeclaration": true,
"MethodDefinition": true,
"ClassDeclaration": true
}
}]*/
/**
* It returns 10
*/
function foo() {
return 10;
}
/**
* It returns 10
*/
var foo = function() {
return 10;
}
var array = [1,2,3];
array.filter(function(item) {
return item > 2;
});
/**
* It returns 10
*/
class Test{
/**
* returns the date
*/
getDate(){}
}
When Not To Use It
If you do not require JSDoc for your functions, then you can leave this rule off.
Related Rules
- [valid-jsdoc](valid-jsdoc.md) Source: http://eslint.org/docs/rules/
Missing space before opening brace. Open
obj.samples.forEach(function(sample){
- Read upRead up
- Exclude checks
Require Or Disallow Space Before Blocks (space-before-blocks)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Consistency is an important part of any style guide. While it is a personal preference where to put the opening brace of blocks, it should be consistent across a whole project. Having an inconsistent style distracts the reader from seeing the important parts of the code.
Rule Details
This rule will enforce consistency of spacing before blocks. It is only applied on blocks that don’t begin on a new line.
- This rule ignores spacing which is between
=>
and a block. The spacing is handled by thearrow-spacing
rule. - This rule ignores spacing which is between a keyword and a block. The spacing is handled by the
keyword-spacing
rule.
Options
This rule takes one argument. If it is "always"
then blocks must always have at least one preceding space. If "never"
then all blocks should never have any preceding space. If different spacing is desired for function
blocks, keyword blocks and classes, an optional configuration object can be passed as the rule argument to
configure the cases separately.
( e.g. { "functions": "never", "keywords": "always", classes: "always" }
)
The default is "always"
.
"always"
The following patterns are considered problems:
/*eslint space-before-blocks: "error"*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try {} catch(a){}
class Foo{
constructor(){}
}
The following patterns are not considered problems:
/*eslint space-before-blocks: "error"*/
if (a) {
b();
}
if (a) {
b();
} else{ /*no error. this is checked by `keyword-spacing` rule.*/
c();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
"never"
The following patterns are considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a) {
b();
}
function a() {}
for (;;) {
b();
}
try {} catch(a) {}
The following patterns are not considered problems:
/*eslint space-before-blocks: ["error", "never"]*/
if (a){
b();
}
function a(){}
for (;;){
b();
}
try{} catch(a){}
class Foo{
constructor(){}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
function a() {}
try {} catch(a){}
class Foo{
constructor() {}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "always", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "always", classes: "never" }]*/
/*eslint-env es6*/
for (;;) {
// ...
}
describe(function(){
// ...
});
class Foo {
constructor(){}
}
The following patterns are considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
function a(){}
try {} catch(a) {}
class Foo {
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "always", "keywords": "never", classes: "never" }
:
/*eslint space-before-blocks: ["error", { "functions": "always", "keywords": "never", classes: "never" }]*/
/*eslint-env es6*/
if (a){
b();
}
var a = function() {}
class Foo{
constructor() {}
}
The following patterns are considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo{
constructor(){}
}
The following patterns are not considered problems when configured { "functions": "never", "keywords": "never", classes: "always" }
:
/*eslint space-before-blocks: ["error", { "functions": "never", "keywords": "never", classes: "always" }]*/
/*eslint-env es6*/
class Foo {
constructor(){}
}
When Not To Use It
You can turn this rule off if you are not concerned with the consistency of spacing before blocks or if you are using the space-after-keywords
rule set to "never"
.
Related Rules
- [keyword-spacing](keyword-spacing.md)
- [arrow-spacing](arrow-spacing.md)
- [brace-style](brace-style.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Expected indentation of 8 space characters but found 10. Open
if (chartsCount < iViz.opts.numOfChartsLimit) {
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 250 exceeds the maximum line length of 80. Open
var hasAttrDataMap = isPatientAttributes ? data_.groups.patient.has_attr_data : data_.groups.sample.has_attr_data;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 405 exceeds the maximum line length of 80. Open
var _caseUIdIndex = self.getCaseIndex('sample', _mutGeneDataObj.study_id, _caseId);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 485 exceeds the maximum line length of 80. Open
if (data_.groups.sample.data[_caseIdIndex].cna_details === undefined) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 598 exceeds the maximum line length of 80. Open
return data_.groups.group_mapping.studyMap[studyId].sample_to_patient[sampleId];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 799 exceeds the maximum line length of 80. Open
_.map(self.getStudyCacseIdsUsingUIDs(vm_.customfilter.type, vm_.customfilter[uidsType]), function(item) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 413 exceeds the maximum line length of 80. Open
if (data_.groups.sample.data[_caseUIdIndex].mutated_genes === undefined) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 423 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseUIdIndex].mutated_genes = [_mutGeneMeta[_uniqueId].index];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 651 exceeds the maximum line length of 80. Open
' Please select less than ' + limit + ' samples, or use another browser.',
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Expected space or tab after '//' in comment. Open
//add 'sample_id' to get mutation count and cna fraction for scatter plot
- Read upRead up
- Exclude checks
Requires or disallows a whitespace (space or tab) beginning a comment (spaced-comment)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Some style guides require or disallow a whitespace immediately after the initial //
or /*
of a comment.
Whitespace after the //
or /*
makes it easier to read text in comments.
On the other hand, commenting out code is easier without having to put a whitespace right after the //
or /*
.
Rule Details
This rule will enforce consistency of spacing after the start of a comment //
or /*
. It also provides several
exceptions for various documentation styles.
Options
The rule takes two options.
-
The first is a string which be either
"always"
or"never"
. The default is"always"
.- If
"always"
then the//
or/*
must be followed by at least one whitespace. - If
"never"
then there should be no whitespace following.
- If
-
This rule can also take a 2nd option, an object with either of the following keys:
"exceptions"
and"markers"
.- The
"exceptions"
value is an array of string patterns which are considered exceptions to the rule. Please note that exceptions are ignored if the first argument is"never"
.
"spaced-comment": ["error", "always", { "exceptions": ["-", "+"] }]
- The
"markers"
value is an array of string patterns which are considered markers for docblock-style comments, such as an additional/
, used to denote documentation read by doxygen, vsdoc, etc. which must have additional characters. The"markers"
array will apply regardless of the value of the first argument, e.g."always"
or"never"
.
"spaced-comment": ["error", "always", { "markers": ["/"] }]
- The
The difference between a marker and an exception is that a marker only appears at the beginning of the comment whereas exceptions can occur anywhere in the comment string.
You can also define separate exceptions and markers for block and line comments:
"spaced-comment": ["error", "always", {
"line": {
"markers": ["/"],
"exceptions": ["-", "+"]
},
"block": {
"markers": ["!"],
"exceptions": ["*"]
}
}]
always
The following patterns are considered problems:
/*eslint spaced-comment: ["error", "always"]*/
//This is a comment with no whitespace at the beginning
/*This is a comment with no whitespace at the beginning */
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always"] */
// This is a comment with a whitespace at the beginning
/* This is a comment with a whitespace at the beginning */
/*
* This is a comment with a whitespace at the beginning
*/
/*
This comment has a newline
*/
/* eslint spaced-comment: ["error", "always"] */
/**
* I am jsdoc
*/
never
The following patterns are considered problems:
/*eslint spaced-comment: ["error", "never"]*/
// This is a comment with a whitespace at the beginning
/* This is a comment with a whitespace at the beginning */
/* \nThis is a comment with a whitespace at the beginning */
The following patterns are not considered problems:
/*eslint spaced-comment: ["error", "never"]*/
/*This is a comment with no whitespace at the beginning */
/*eslint spaced-comment: ["error", "never"]*/
/**
* I am jsdoc
*/
exceptions
The following patterns are considered problems:
/* eslint spaced-comment: ["error", "always", { "block": { "exceptions": ["-"] } }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-", "+"] }] */
//------++++++++
// Comment block
//------++++++++
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-", "+"] }] */
/*------++++++++*/
/* Comment block */
/*------++++++++*/
/* eslint spaced-comment: ["error", "always", { "line": { "exceptions": ["-+"] } }] */
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-"] }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "line": { "exceptions": ["-"] } }] */
//--------------
// Comment block
//--------------
/* eslint spaced-comment: ["error", "always", { "exceptions": ["*"] }] */
/****************
* Comment block
****************/
/* eslint spaced-comment: ["error", "always", { "exceptions": ["-+"] }] */
//-+-+-+-+-+-+-+
// Comment block
//-+-+-+-+-+-+-+
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
/* eslint spaced-comment: ["error", "always", { "block": { "exceptions": ["-+"] } }] */
/*-+-+-+-+-+-+-+*/
// Comment block
/*-+-+-+-+-+-+-+*/
markers
The following patterns are considered problems:
/* eslint spaced-comment: ["error", "always", { "markers": ["/"] }] */
///This is a comment with a marker but without whitespace
The following patterns are not considered problems:
/* eslint spaced-comment: ["error", "always", { "markers": ["/"] }] */
/// This is a comment with a marker
/*eslint spaced-comment: ["error", "never", { "markers": ["!<"] }]*/
//!<this is a line comment with marker block subsequent lines are ignored></this>
/* eslint spaced-comment: ["error", "always", { "markers": ["global"] }] */
/*global ABC*/
Related Rules
- [spaced-line-comment](spaced-line-comment.md) Source: http://eslint.org/docs/rules/
Trailing spaces not allowed. Open
// Filter 'undefined' case index
- Read upRead up
- Exclude checks
Disallow trailing spaces at the end of lines (no-trailing-spaces)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Sometimes in the course of editing files, you can end up with extra whitespace at the end of lines. These whitespace differences can be picked up by source control systems and flagged as diffs, causing frustration for developers. While this extra whitespace causes no functional issues, many code conventions require that trailing spaces be removed before checkin.
Rule Details
The following patterns are considered problems:
/*eslint no-trailing-spaces: "error"*/
// spaces, tabs and unicode whitespaces
// are not allowed at the end of lines
var foo = 0;//•••••
var baz = 5;//••
The following patterns are not considered problems:
/*eslint no-trailing-spaces: "error"*/
var foo = 0;
var baz = 5;
Options
There is one option for this rule, skipBlankLines
. When set to true, the rule will not flag any lines that are made up purely of whitespace. In short, if a line is zero-length after being trimmed of whitespace, then the rule will not flag that line when skipBlankLines
is enabled.
You can enable this option in your config like this:
{
"no-trailing-spaces": ["error", { "skipBlankLines": true }]
}
With this option enabled, The following patterns are not considered problems:
/*eslint no-trailing-spaces: ["error", { "skipBlankLines": true }]*/
var foo = 0;
//••••
var baz = 5;
Source: http://eslint.org/docs/rules/
Expected indentation of 12 space characters but found 10. Open
case 2:
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Expected indentation of 14 space characters but found 12. Open
_altType = 'AMP';
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 529 exceeds the maximum line length of 80. Open
def.resolve(self.extractMutationData(_data, window.iviz.datamanager.getAllMutatedGeneSamples()));
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
QueryByGeneTextArea.getGenes(), includeCases)
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 223 exceeds the maximum line length of 80. Open
$.when(iViz.getDataWithAttrs(groupNdxData_.type, attrIds)).then(function(selectedData_) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 269 exceeds the maximum line length of 80. Open
var _data = isPatientAttributes ? data_.groups.patient.data : data_.groups.sample.data;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 515 exceeds the maximum line length of 80. Open
"molecularProfileId": window.iviz.datamanager.getCNAProfileIdByStudyId(studyId),
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 581 exceeds the maximum line length of 80. Open
var _uid = data_.groups.group_mapping.studyMap[b][type + '_to_uid'][case_id];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing space before value for key 'delay'. Open
delay:10000
- Read upRead up
- Exclude checks
enforce consistent spacing between keys and values in object literal properties (key-spacing)
This rule enforces spacing around the colon in object literal properties. It can verify each property individually, or it can ensure horizontal alignment of adjacent properties in an object literal.
Rule Details
This rule enforces consistent spacing between keys and values in object literal properties. In the case of long lines, it is acceptable to add a new line wherever whitespace is allowed.
Options
This rule has an object option:
-
"beforeColon": false
(default) disallows spaces between the key and the colon in object literals -
"beforeColon": true
requires at least one space between the key and the colon in object literals -
"afterColon": true
(default) requires at least one space between the colon and the value in object literals -
"afterColon": false
disallows spaces between the colon and the value in object literals -
"mode": strict
(default) enforces exactly one space before or after colons in object literals -
"mode": minimum
enforces one or more spaces before or after colons in object literals -
"align": "value"
enforces horizontal alignment of values in object literals -
"align": "colon"
enforces horizontal alignment of both colons and values in object literals. -
"singleLine"
specifies a spacing style for single-line object literals -
"multiLine"
specifies a spacing style for multi-line object literals
Please note that you can either use the top-level options or the grouped options (singleLine
and multiLine
) but not both.
beforeColon
Examples of incorrect code for this rule with the default { "beforeColon": false }
option:
/*eslint key-spacing: ["error", { "beforeColon": false }]*/
var obj = { "foo" : 42 };
Examples of correct code for this rule with the default { "beforeColon": false }
option:
/*eslint key-spacing: ["error", { "beforeColon": false }]*/
var obj = { "foo": 42 };
Examples of incorrect code for this rule with the { "beforeColon": true }
option:
/*eslint key-spacing: ["error", { "beforeColon": true }]*/
var obj = { "foo": 42 };
Examples of correct code for this rule with the { "beforeColon": true }
option:
/*eslint key-spacing: ["error", { "beforeColon": true }]*/
var obj = { "foo" : 42 };
afterColon
Examples of incorrect code for this rule with the default { "afterColon": true }
option:
/*eslint key-spacing: ["error", { "afterColon": true }]*/
var obj = { "foo":42 };
Examples of correct code for this rule with the default { "afterColon": true }
option:
/*eslint key-spacing: ["error", { "afterColon": true }]*/
var obj = { "foo": 42 };
Examples of incorrect code for this rule with the { "afterColon": false }
option:
/*eslint key-spacing: ["error", { "afterColon": false }]*/
var obj = { "foo": 42 };
Examples of correct code for this rule with the { "afterColon": false }
option:
/*eslint key-spacing: ["error", { "afterColon": false }]*/
var obj = { "foo":42 };
mode
Examples of incorrect code for this rule with the default { "mode": "strict" }
option:
/*eslint key-spacing: ["error", { "mode": "strict" }]*/
call({
foobar: 42,
bat: 2 * 2
});
Examples of correct code for this rule with the default { "mode": "strict" }
option:
/*eslint key-spacing: ["error", { "mode": "strict" }]*/
call({
foobar: 42,
bat: 2 * 2
});
Examples of correct code for this rule with the { "mode": "minimum" }
option:
/*eslint key-spacing: ["error", { "mode": "minimum" }]*/
call({
foobar: 42,
bat: 2 * 2
});
align
Examples of incorrect code for this rule with the { "align": "value" }
option:
/*eslint key-spacing: ["error", { "align": "value" }]*/
var obj = {
a: value,
bcde: 42,
fg : foo()
};
Examples of correct code for this rule with the { "align": "value" }
option:
/*eslint key-spacing: ["error", { "align": "value" }]*/
var obj = {
a: value,
bcde: 42,
fg: foo(),
h: function() {
return this.a;
},
ijkl: 'Non-consecutive lines form a new group'
};
var obj = { a: "foo", longPropertyName: "bar" };
Examples of incorrect code for this rule with the { "align": "colon" }
option:
/*eslint key-spacing: ["error", { "align": "colon" }]*/
call({
foobar: 42,
bat: 2 * 2
});
Examples of correct code for this rule with the { "align": "colon" }
option:
/*eslint key-spacing: ["error", { "align": "colon" }]*/
call({
foobar: 42,
bat : 2 * 2
});
singleLine and multiLine
Examples of correct code for this rule with sample { "singleLine": { }, "multiLine": { } }
options:
/*eslint "key-spacing": [2, {
"singleLine": {
"beforeColon": false,
"afterColon": true
},
"multiLine": {
"beforeColon": true,
"afterColon": true,
"align": "colon"
}
}]*/
var obj = { one: 1, "two": 2, three: 3 };
var obj2 = {
"two" : 2,
three : 3
};
When Not To Use It
If you have another convention for property spacing that might not be consistent with the available options, or if you want to permit multiple styles concurrently you can safely disable this rule. Source: http://eslint.org/docs/rules/
Line 314 exceeds the maximum line length of 80. Open
var _data = isPatientAttributes ? data_.groups.patient.data : data_.groups.sample.data;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 382 exceeds the maximum line length of 80. Open
_.each(_.difference(attrIds, Object.keys(attrsFromServer)), function(_attrId) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Strings must use singlequote. Open
"sampleId": sampleId
- Read upRead up
- Exclude checks
Enforce Quote Style (quotes)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:
/*eslint-env es6*/
var double = "double";
var single = 'single';
var backtick = `backtick`; // ES6 only
Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).
Many codebases require strings to be defined in a consistent manner.
Rule Details
This rule is aimed at ensuring consistency of string quotes and as such will report a problem when an inconsistent style is found.
The rule configuration takes up to two options:
- The first option is
"double"
,"single"
or"backtick"
for double-quotes, single-quotes or backticks respectively. The default is"double"
. - The second option takes two options:
-
"avoidEscape"
: When using"avoidEscape"
, this rule will not report a problem when a string is using single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise. For example, if you specify"double"
and"avoidEscape"
, the string'He said, "hi!"'
is not considered a problem because using double quotes for that string would require escaping the double quotes inside of the string. This option is off by default. -
"allowTemplateLiterals"
: when using"allowTemplateLiterals"
, this rule will not report a problem when a string is using backticks and option one is either"double"
or"single"
.
-
When using "single"
or "double"
, template literals that don't contain a substitution, don't contain a line break and aren't tagged templates, are flagged as problems, even with the "avoidEscape"
option. However they are not problems when "allowTemplateLiterals"
is used.
Configuration looks like this:
[2, "single", {"avoidEscape": true, "allowTemplateLiterals": true}]
Deprecation notice: The avoid-escape
option is a deprecated syntax and you should use the object form instead.
The following patterns are considered problems:
/*eslint quotes: ["error", "double"]*/
var single = 'single';
var unescaped = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single"]*/
var double = "double";
var unescaped = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var single = 'single';
var double = "double";
The following patterns are not considered problems:
/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/
var double = "double";
var backtick = `back\ntick`; // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag
/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/
var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"allowTemplateLiterals": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"allowTemplateLiterals": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/
var backtick = `backtick`;
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var double = "a string containing `backtick` quotes"
When Not To Use It
If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/
Trailing spaces not allowed. Open
- Read upRead up
- Exclude checks
Disallow trailing spaces at the end of lines (no-trailing-spaces)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
Sometimes in the course of editing files, you can end up with extra whitespace at the end of lines. These whitespace differences can be picked up by source control systems and flagged as diffs, causing frustration for developers. While this extra whitespace causes no functional issues, many code conventions require that trailing spaces be removed before checkin.
Rule Details
The following patterns are considered problems:
/*eslint no-trailing-spaces: "error"*/
// spaces, tabs and unicode whitespaces
// are not allowed at the end of lines
var foo = 0;//•••••
var baz = 5;//••
The following patterns are not considered problems:
/*eslint no-trailing-spaces: "error"*/
var foo = 0;
var baz = 5;
Options
There is one option for this rule, skipBlankLines
. When set to true, the rule will not flag any lines that are made up purely of whitespace. In short, if a line is zero-length after being trimmed of whitespace, then the rule will not flag that line when skipBlankLines
is enabled.
You can enable this option in your config like this:
{
"no-trailing-spaces": ["error", { "skipBlankLines": true }]
}
With this option enabled, The following patterns are not considered problems:
/*eslint no-trailing-spaces: ["error", { "skipBlankLines": true }]*/
var foo = 0;
//••••
var baz = 5;
Source: http://eslint.org/docs/rules/
Line 425 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseUIdIndex].mutated_genes.push(_mutGeneMeta[_uniqueId].index);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 551 exceeds the maximum line length of 80. Open
$.when(window.iviz.datamanager.getSampleClinicalData(['MUTATION_COUNT', 'FRACTION_GENOME_ALTERED']))
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 577 exceeds the maximum line length of 80. Open
return data_.groups.group_mapping.studyMap[study_id].patient_to_uid[case_id];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
new Notification().createNotification('Following sample(s) might have been deleted/updated with the recent data updates<br/>'+str, {
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Line 422 exceeds the maximum line length of 80. Open
if (data_.groups.sample.data[_caseUIdIndex].mutated_genes === undefined) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 494 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseIdIndex].cna_details = [_cnaMeta[_uniqueId].index];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 536 exceeds the maximum line length of 80. Open
def.resolve(self.extractCnaData(_data, window.iviz.datamanager.getAllCNASamples()));
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 633 exceeds the maximum line length of 80. Open
'#navCaseIds=' + getNavCaseIdsStr(_selectedCasesMap, _selectedCaseIds, false).str;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 748 exceeds the maximum line length of 80. Open
_selectedStudyCasesMap[_caseDataObj.study_id].id = _caseDataObj.study_id;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Expected indentation of 6 space characters but found 10. Open
QueryByGeneUtil. query (cohortIdsList ? cohortIdsList: window.cohortIdsList, this.stat(),
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Unexpected whitespace before property query. Open
QueryByGeneUtil. query (cohortIdsList ? cohortIdsList: window.cohortIdsList, this.stat(),
- Read upRead up
- Exclude checks
Disallow whitespace before properties (no-whitespace-before-property)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows whitespace between objects and their properties. However, inconsistent spacing can make code harder to read and can lead to errors.
foo. bar .baz . quz
Rule Details
This rule alerts for whitespace around the dot or before the opening bracket before properties of objects if they are on the same line. It does not alert for whitespace when the object and property are on separate lines, as it is common to add newlines to longer chains of properties:
foo
.bar()
.baz()
.qux()
The following patterns are considered problems when this rule is turned on:
/*eslint no-whitespace-before-property: "error"*/
foo [bar]
foo. bar
foo .bar
foo. bar. baz
foo. bar()
.baz()
foo
.bar(). baz()
And the following patterns are not considered problems:
/*eslint no-whitespace-before-property: "error"*/
foo.bar
foo[bar]
foo[ bar ]
foo.bar.baz
foo
.bar().baz()
foo
.bar()
.baz()
foo.
bar().
baz()
When Not To Use It
Turn this rule off if you do not care about allowing whitespace around the dot or before the opening bracket before properties of objects if they are on the same line. Source: http://eslint.org/docs/rules/
Line 333 exceeds the maximum line length of 80. Open
var caseIndex = self_.getCaseIndex(type, _dataObj.study_id, _dataObj[idType]);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 352 exceeds the maximum line length of 80. Open
&& ['CANCER_TYPE', 'CANCER_TYPE_DETAILED'].indexOf(_attrId) === -1) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
'&&' should be placed at the end of the line. Open
&& ['CANCER_TYPE', 'CANCER_TYPE_DETAILED'].indexOf(_attrId) === -1) {
- Read upRead up
- Exclude checks
Operator Linebreak (operator-linebreak)
When a statement is too long to fit on a single line, line breaks are generally inserted next to the operators separating expressions. The first style coming to mind would be to place the operator at the end of the line, following the english punctuation rules.
var fullHeight = borderTop +
innerHeight +
borderBottom;
Some developers find that placing operators at the beginning of the line makes the code more readable.
var fullHeight = borderTop
+ innerHeight
+ borderBottom;
Rule Details
The operator-linebreak
rule is aimed at enforcing a particular operator line break style. As such, it warns whenever it sees a binary operator or assignment that does not adhere to a particular style: either placing linebreaks after or before the operators.
Options
The rule takes two options, a string, which can be "after"
, "before"
or "none"
where the default is "after"
and an object for more fine-grained configuration.
You can set the style in configuration like this:
"operator-linebreak": ["error", "before", { "overrides": { "?": "after" } }]
The default configuration is to enforce line breaks after the operator except for the ternary operator ?
and :
following that.
"after"
This is the default setting for this rule. This option requires the line break to be placed after the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "after"]*/
foo = 1
+
2;
foo = 1
+ 2;
foo
= 5;
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "after"]*/
foo = 1 + 2;
foo = 1 +
2;
foo =
5;
if (someCondition ||
otherCondition) {
}
answer = everything ?
42 :
foo;
"before"
This option requires the line break to be placed before the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "before"]*/
foo = 1 +
2;
foo =
5;
if (someCondition ||
otherCondition) {
}
answer = everything ?
42 :
foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "before"]*/
foo = 1 + 2;
foo = 1
+ 2;
foo
= 5;
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
"none"
This option disallows line breaks on either side of the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "none"]*/
foo = 1 +
2;
foo = 1
+ 2;
if (someCondition ||
otherCondition) {
}
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
answer = everything ?
42 :
foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "none"]*/
foo = 1 + 2;
foo = 5;
if (someCondition || otherCondition) {
}
answer = everything ? 42 : foo;
Fine-grained control
The rule allows you to have even finer-grained control over individual operators by specifying an overrides
dictionary:
"operator-linebreak": ["error", "before", { "overrides": { "?": "after", "+=": "none" } }]
This would override the global setting for that specific operator.
"ignore" override
This option is only supported using overrides and ignores line breaks on either side of the operator.
While using this setting, the following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "after", { "overrides": { "?": "ignore", ":": "ignore"} }]*/
answer = everything ?
42
: foo;
answer = everything
?
42
:
foo;
When Not To Use It
If your project will not be using a common operator line break style, turn this rule off.
Related Rules
- [comma-style](comma-style.md) Source: http://eslint.org/docs/rules/
Properties shouldn't be quoted as all quotes are redundant. Open
tableData_.mutated_genes.allSamples.push({
- Read upRead up
- Exclude checks
Quoting Style for Property Names (quote-props)
Object literal property names can be defined in two ways: using literals or using strings. For example, these two objects are equivalent:
var object1 = {
property: true
};
var object2 = {
"property": true
};
In many cases, it doesn't matter if you choose to use an identifier instead of a string or vice-versa. Even so, you might decide to enforce a consistent style in your code.
There are, however, some occasions when you must use quotes:
- If you are using an ECMAScript 3 JavaScript engine (such as IE8) and you want to use a keyword (such as
if
) as a property name. This restriction was removed in ECMAScript 5. - You want to use a non-identifier character in your property name, such as having a property with a space like
"one two"
.
Another example where quotes do matter is when using numeric literals as property keys:
var object = {
1e2: 1,
100: 2
};
This may look alright at first sight, but this code in fact throws a syntax error in ECMAScript 5 strict mode. This happens because 1e2
and 100
are coerced into strings before getting used as the property name. Both String(1e2)
and String(100)
happen to be equal to "100"
, which causes the "Duplicate data property in object literal not allowed in strict mode" error. Issues like that can be tricky to debug, so some prefer to require quotes around all property names.
Rule Details
This rule aims to enforce use of quotes in property names and as such will flag any properties that don't use quotes (default behavior).
Options
There are four behaviors for this rule: "always"
(default), "as-needed"
, "consistent"
and "consistent-as-needed"
. You can define these options in your configuration as:
{
"quote-props": ["error", "as-needed"]
}
"always"
When configured with "always"
as the first option (the default), quoting for all properties will be enforced. Some believe that ensuring property names in object literals are always wrapped in quotes is generally a good idea, since depending on the property name you may need to quote them anyway. Consider this example:
var object = {
foo: "bar",
baz: 42,
"qux-lorem": true
};
Here, the properties foo
and baz
are not wrapped in quotes, but qux-lorem
is, because it doesn’t work without the quotes. This is rather inconsistent. Instead, you may prefer to quote names of all properties:
var object = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
or, if you prefer single quotes:
var object = {
'foo': 'bar',
'baz': 42,
'qux-lorem': true
};
When configured with "always"
as the first option (the default), quoting for all properties will be enforced. The following patterns are considered problems:
/*eslint quote-props: ["error", "always"]*/
var object = {
foo: "bar",
baz: 42,
"qux-lorem": true
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "always"]*/
/*eslint-env es6*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42,
'qux-lorem': true
};
var object3 = {
foo() {
return;
}
};
"as-needed"
When configured with "as-needed"
as the first option, quotes will be enforced when they are strictly required, and unnecessary quotes will cause warnings. The following patterns are considered problems:
/*eslint quote-props: ["error", "as-needed"]*/
var object = {
"a": 0,
"0": 0,
"true": 0,
"null": 0
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "as-needed"]*/
/*eslint-env es6*/
var object1 = {
"a-b": 0,
"0x0": 0,
"1e2": 0
};
var object2 = {
foo: 'bar',
baz: 42,
true: 0,
0: 0,
'qux-lorem': true
};
var object3 = {
foo() {
return;
}
};
When the "as-needed"
mode is selected, an additional keywords
option can be provided. This flag indicates whether language keywords should be quoted as properties. By default it is set to false
.
{
"quote-props": ["error", "as-needed", { "keywords": true }]
}
When keywords
is set to true
, the following patterns become problems:
/*eslint quote-props: ["error", "as-needed", { "keywords": true }]*/
var x = {
while: 1,
volatile: "foo"
};
Another modifier for this rule is the unnecessary
option which defaults to true
. Setting this to false
will prevent the rule from complaining about unnecessarily quoted properties. This comes in handy when you only care about quoting keywords.
{
"quote-props": ["error", "as-needed", { "keywords": true, "unnecessary": false }]
}
When unnecessary
is set to false
, the following patterns stop being problems:
/*eslint quote-props: ["error", "as-needed", { "keywords": true, "unnecessary": false }]*/
var x = {
"while": 1,
"foo": "bar" // Would normally have caused a warning
};
A numbers
flag, with default value false
, can also be used as a modifier for the "as-needed"
mode. When it is set to true
, numeric literals should always be quoted.
{
"quote-props": ["error", "as-needed", {"numbers": true}]
}
When numbers
is set to true
, the following patterns become problems:
/*eslint quote-props: ["error", "as-needed", { "numbers": true }]*/
var x = {
100: 1
}
and the following patterns stop being problems:
var x = {
"100": 1
}
"consistent"
When configured with "consistent"
, the patterns below are considered problems. Basically "consistent"
means all or no properties are expected to be quoted, in other words quoting style can't be mixed within an object. Please note the latter situation (no quotation at all) isn't always possible as some property names require quoting.
/*eslint quote-props: ["error", "consistent"]*/
var object1 = {
foo: "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
baz: 42
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "consistent"]*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42
};
var object3 = {
foo: 'bar',
baz: 42
};
"consistent-as-needed"
When configured with "consistent-as-needed"
, the behavior is similar to "consistent"
with one difference. Namely, properties' quoting should be consistent (as in "consistent"
) but whenever all quotes are redundant a warning is raised. In other words if at least one property name has to be quoted (like qux-lorem
) then all property names must be quoted, otherwise no properties can be quoted. The following patterns are considered problems:
/*eslint quote-props: ["error", "consistent-as-needed"]*/
var object1 = {
foo: "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "consistent-as-needed"]*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
foo: 'bar',
baz: 42
};
When the "consistent-as-needed"
mode is selected, an additional keywords
option can be provided. This flag indicates whether language keywords can be used unquoted as properties. By default it is set to false
.
{
"quote-props": ["error", "consistent-as-needed", { "keywords": true }]
}
When keywords
is set to true
, the following patterns are considered problems:
/*eslint quote-props: ["error", "consistent-as-needed", { "keywords": true }]*/
var x = {
while: 1,
volatile: "foo"
};
When Not To Use It
If you don't care if property names are consistently wrapped in quotes or not, and you don't target legacy ES3 environments, turn this rule off.
Further Reading
Line 443 exceeds the maximum line length of 80. Open
"molecularProfileId": window.iviz.datamanager.getMutationProfileIdByStudyId(studyId),
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 206 exceeds the maximum line length of 80. Open
$.when(iViz.getDataWithAttrs(group.type, _attrIds)).then(function(selectedData_) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 414 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseUIdIndex].mutated_genes = [_mutGeneMetaIndex];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Expected indentation of 12 space characters but found 10. Open
default:
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 486 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseIdIndex].cna_details = [_cnaMetaIndex];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 496 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseIdIndex].cna_details.push(_cnaMeta[_uniqueId].index);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 575 exceeds the maximum line length of 80. Open
return data_.groups.group_mapping.studyMap[study_id].sample_to_uid[case_id];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 601 exceeds the maximum line length of 80. Open
return data_.groups.group_mapping.studyMap[studyId].patient_to_sample[patientId];
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Missing semicolon. Open
browserName = 'Microsoft Edge'
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Strings must use singlequote. Open
"molecularProfileId": window.iviz.datamanager.getMutationProfileIdByStudyId(studyId),
- Read upRead up
- Exclude checks
Enforce Quote Style (quotes)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:
/*eslint-env es6*/
var double = "double";
var single = 'single';
var backtick = `backtick`; // ES6 only
Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).
Many codebases require strings to be defined in a consistent manner.
Rule Details
This rule is aimed at ensuring consistency of string quotes and as such will report a problem when an inconsistent style is found.
The rule configuration takes up to two options:
- The first option is
"double"
,"single"
or"backtick"
for double-quotes, single-quotes or backticks respectively. The default is"double"
. - The second option takes two options:
-
"avoidEscape"
: When using"avoidEscape"
, this rule will not report a problem when a string is using single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise. For example, if you specify"double"
and"avoidEscape"
, the string'He said, "hi!"'
is not considered a problem because using double quotes for that string would require escaping the double quotes inside of the string. This option is off by default. -
"allowTemplateLiterals"
: when using"allowTemplateLiterals"
, this rule will not report a problem when a string is using backticks and option one is either"double"
or"single"
.
-
When using "single"
or "double"
, template literals that don't contain a substitution, don't contain a line break and aren't tagged templates, are flagged as problems, even with the "avoidEscape"
option. However they are not problems when "allowTemplateLiterals"
is used.
Configuration looks like this:
[2, "single", {"avoidEscape": true, "allowTemplateLiterals": true}]
Deprecation notice: The avoid-escape
option is a deprecated syntax and you should use the object form instead.
The following patterns are considered problems:
/*eslint quotes: ["error", "double"]*/
var single = 'single';
var unescaped = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single"]*/
var double = "double";
var unescaped = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var single = 'single';
var double = "double";
The following patterns are not considered problems:
/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/
var double = "double";
var backtick = `back\ntick`; // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag
/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/
var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"allowTemplateLiterals": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"allowTemplateLiterals": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/
var backtick = `backtick`;
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var double = "a string containing `backtick` quotes"
When Not To Use It
If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/
Strings must use singlequote. Open
"sampleId": sampleId
- Read upRead up
- Exclude checks
Enforce Quote Style (quotes)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:
/*eslint-env es6*/
var double = "double";
var single = 'single';
var backtick = `backtick`; // ES6 only
Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).
Many codebases require strings to be defined in a consistent manner.
Rule Details
This rule is aimed at ensuring consistency of string quotes and as such will report a problem when an inconsistent style is found.
The rule configuration takes up to two options:
- The first option is
"double"
,"single"
or"backtick"
for double-quotes, single-quotes or backticks respectively. The default is"double"
. - The second option takes two options:
-
"avoidEscape"
: When using"avoidEscape"
, this rule will not report a problem when a string is using single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise. For example, if you specify"double"
and"avoidEscape"
, the string'He said, "hi!"'
is not considered a problem because using double quotes for that string would require escaping the double quotes inside of the string. This option is off by default. -
"allowTemplateLiterals"
: when using"allowTemplateLiterals"
, this rule will not report a problem when a string is using backticks and option one is either"double"
or"single"
.
-
When using "single"
or "double"
, template literals that don't contain a substitution, don't contain a line break and aren't tagged templates, are flagged as problems, even with the "avoidEscape"
option. However they are not problems when "allowTemplateLiterals"
is used.
Configuration looks like this:
[2, "single", {"avoidEscape": true, "allowTemplateLiterals": true}]
Deprecation notice: The avoid-escape
option is a deprecated syntax and you should use the object form instead.
The following patterns are considered problems:
/*eslint quotes: ["error", "double"]*/
var single = 'single';
var unescaped = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single"]*/
var double = "double";
var unescaped = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var single = 'single';
var double = "double";
The following patterns are not considered problems:
/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/
var double = "double";
var backtick = `back\ntick`; // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag
/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/
var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"allowTemplateLiterals": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"allowTemplateLiterals": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/
var backtick = `backtick`;
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var double = "a string containing `backtick` quotes"
When Not To Use It
If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/
Expected indentation of 12 space characters but found 10. Open
case -2:
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Expected indentation of 14 space characters but found 12. Open
_altType = 'DEL';
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Expected indentation of 14 space characters but found 12. Open
break;
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 493 exceeds the maximum line length of 80. Open
if (data_.groups.sample.data[_caseIdIndex].cna_details === undefined) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 641 exceeds the maximum line length of 80. Open
var limit = getNavCaseIdsStr(_selectedCasesMap, _selectedCaseIds, true).limit;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 752 exceeds the maximum line length of 80. Open
_selectedStudyCasesMap[_caseDataObj.study_id].samples.push(_caseDataObj.sample_id);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Strings must use singlequote. Open
"molecularProfileId": window.iviz.datamanager.getCNAProfileIdByStudyId(studyId),
- Read upRead up
- Exclude checks
Enforce Quote Style (quotes)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:
/*eslint-env es6*/
var double = "double";
var single = 'single';
var backtick = `backtick`; // ES6 only
Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).
Many codebases require strings to be defined in a consistent manner.
Rule Details
This rule is aimed at ensuring consistency of string quotes and as such will report a problem when an inconsistent style is found.
The rule configuration takes up to two options:
- The first option is
"double"
,"single"
or"backtick"
for double-quotes, single-quotes or backticks respectively. The default is"double"
. - The second option takes two options:
-
"avoidEscape"
: When using"avoidEscape"
, this rule will not report a problem when a string is using single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise. For example, if you specify"double"
and"avoidEscape"
, the string'He said, "hi!"'
is not considered a problem because using double quotes for that string would require escaping the double quotes inside of the string. This option is off by default. -
"allowTemplateLiterals"
: when using"allowTemplateLiterals"
, this rule will not report a problem when a string is using backticks and option one is either"double"
or"single"
.
-
When using "single"
or "double"
, template literals that don't contain a substitution, don't contain a line break and aren't tagged templates, are flagged as problems, even with the "avoidEscape"
option. However they are not problems when "allowTemplateLiterals"
is used.
Configuration looks like this:
[2, "single", {"avoidEscape": true, "allowTemplateLiterals": true}]
Deprecation notice: The avoid-escape
option is a deprecated syntax and you should use the object form instead.
The following patterns are considered problems:
/*eslint quotes: ["error", "double"]*/
var single = 'single';
var unescaped = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single"]*/
var double = "double";
var unescaped = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var single = 'single';
var double = "double";
The following patterns are not considered problems:
/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/
var double = "double";
var backtick = `back\ntick`; // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag
/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/
var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution
/*eslint quotes: ["error", "double", {"avoidEscape": true}]*/
var single = 'a string containing "double" quotes';
/*eslint quotes: ["error", "single", {"avoidEscape": true}]*/
var double = "a string containing 'single' quotes";
/*eslint quotes: ["error", "double", {"allowTemplateLiterals": true}]*/
var single = 'single';
var single = `single`;
/*eslint quotes: ["error", "single", {"allowTemplateLiterals": true}]*/
var double = "double";
var double = `double`;
/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/
var backtick = `backtick`;
/*eslint quotes: ["error", "backtick", {"avoidEscape": true}]*/
var double = "a string containing `backtick` quotes"
When Not To Use It
If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/
More than 1 blank line not allowed. Open
- Read upRead up
- Exclude checks
Disallows multiple blank lines (no-multiple-empty-lines)
Some developers prefer to have multiple blank lines removed, while others feel that it helps improve readability. Whitespace is useful for separating logical sections of code, but excess whitespace takes up more of the screen.
Rule Details
This rule aims to reduce the scrolling required when reading through your code. It will warn when the maximum amount of empty lines has been exceeded.
Options
The second argument can be used to configure this rule:
-
max
sets the maximum number of consecutive blank lines. -
maxEOF
can be used to set a different number for the end of file. The last blank lines will then be treated differently. If omitted, themax
option is applied at the end of the file. -
maxBOF
can be used to set a different number for the beginning of the file. If omitted, the 'max' option is applied at the beginning of the file.
max
In the following example, the error
is the severity of the rule, and the
max
property is the maximum number of empty lines (2 in this example).
"no-multiple-empty-lines": ["error", {"max": 2}]
The following patterns are considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2}]*/
var foo = 5;
var bar = 3;
The following patterns are not considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2}]*/
var foo = 5;
var bar = 3;
maxEOF
"no-multiple-empty-lines": ["error", {"max": 2, "maxEOF": 1}]
The following patterns are considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2, maxEOF: 1}]*/
var foo = 5;
var bar = 3;
The following patterns are not considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2, maxEOF: 1}]*/
var foo = 5;
var bar = 3;
maxBOF
"no-multiple-empty-lines": ["error", {"max": 2, "maxBOF": 0}]
The following patterns are considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2, maxBOF: 0}]*/
var foo = 5;
var bar = 3;
The following patterns are not considered problems:
/*eslint no-multiple-empty-lines: ["error", {max: 2, maxBOF: 0}]*/
var foo = 5;
var bar = 3;
When Not To Use It
If you do not care about extra blank lines, turn this off. Source: http://eslint.org/docs/rules/
Unexpected space between function name and paren. Open
QueryByGeneUtil. query (cohortIdsList ? cohortIdsList: window.cohortIdsList, this.stat(),
- Read upRead up
- Exclude checks
Disallow Spaces in Function Calls (no-spaced-func)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While it's possible to have whitespace between the name of a function and the parentheses that execute it, such patterns tend to look more like errors.
Rule Details
This rule does not allow gaps between the function identifier and application.
fn ()
The following patterns are considered problems:
/*eslint no-spaced-func: "error"*/
fn ()
fn
()
The following patterns are not considered problems:
/*eslint no-spaced-func: "error"*/
fn()
Source: http://eslint.org/docs/rules/
'||' should be placed at the end of the line. Open
|| vm_.customfilter.patientUids.length > 0) {
- Read upRead up
- Exclude checks
Operator Linebreak (operator-linebreak)
When a statement is too long to fit on a single line, line breaks are generally inserted next to the operators separating expressions. The first style coming to mind would be to place the operator at the end of the line, following the english punctuation rules.
var fullHeight = borderTop +
innerHeight +
borderBottom;
Some developers find that placing operators at the beginning of the line makes the code more readable.
var fullHeight = borderTop
+ innerHeight
+ borderBottom;
Rule Details
The operator-linebreak
rule is aimed at enforcing a particular operator line break style. As such, it warns whenever it sees a binary operator or assignment that does not adhere to a particular style: either placing linebreaks after or before the operators.
Options
The rule takes two options, a string, which can be "after"
, "before"
or "none"
where the default is "after"
and an object for more fine-grained configuration.
You can set the style in configuration like this:
"operator-linebreak": ["error", "before", { "overrides": { "?": "after" } }]
The default configuration is to enforce line breaks after the operator except for the ternary operator ?
and :
following that.
"after"
This is the default setting for this rule. This option requires the line break to be placed after the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "after"]*/
foo = 1
+
2;
foo = 1
+ 2;
foo
= 5;
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "after"]*/
foo = 1 + 2;
foo = 1 +
2;
foo =
5;
if (someCondition ||
otherCondition) {
}
answer = everything ?
42 :
foo;
"before"
This option requires the line break to be placed before the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "before"]*/
foo = 1 +
2;
foo =
5;
if (someCondition ||
otherCondition) {
}
answer = everything ?
42 :
foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "before"]*/
foo = 1 + 2;
foo = 1
+ 2;
foo
= 5;
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
"none"
This option disallows line breaks on either side of the operator.
While using this setting, the following patterns are considered problems:
/*eslint operator-linebreak: ["error", "none"]*/
foo = 1 +
2;
foo = 1
+ 2;
if (someCondition ||
otherCondition) {
}
if (someCondition
|| otherCondition) {
}
answer = everything
? 42
: foo;
answer = everything ?
42 :
foo;
The following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "none"]*/
foo = 1 + 2;
foo = 5;
if (someCondition || otherCondition) {
}
answer = everything ? 42 : foo;
Fine-grained control
The rule allows you to have even finer-grained control over individual operators by specifying an overrides
dictionary:
"operator-linebreak": ["error", "before", { "overrides": { "?": "after", "+=": "none" } }]
This would override the global setting for that specific operator.
"ignore" override
This option is only supported using overrides and ignores line breaks on either side of the operator.
While using this setting, the following patterns are not considered problems:
/*eslint operator-linebreak: ["error", "after", { "overrides": { "?": "ignore", ":": "ignore"} }]*/
answer = everything ?
42
: foo;
answer = everything
?
42
:
foo;
When Not To Use It
If your project will not be using a common operator line break style, turn this rule off.
Related Rules
- [comma-style](comma-style.md) Source: http://eslint.org/docs/rules/
Line 301 exceeds the maximum line length of 80. Open
$.when(window.iviz.datamanager.getClinicalData(_attrIds, (_type === 'patient')))
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Properties shouldn't be quoted as all quotes are redundant. Open
tableData_.cna_details.allSamples.push({
- Read upRead up
- Exclude checks
Quoting Style for Property Names (quote-props)
Object literal property names can be defined in two ways: using literals or using strings. For example, these two objects are equivalent:
var object1 = {
property: true
};
var object2 = {
"property": true
};
In many cases, it doesn't matter if you choose to use an identifier instead of a string or vice-versa. Even so, you might decide to enforce a consistent style in your code.
There are, however, some occasions when you must use quotes:
- If you are using an ECMAScript 3 JavaScript engine (such as IE8) and you want to use a keyword (such as
if
) as a property name. This restriction was removed in ECMAScript 5. - You want to use a non-identifier character in your property name, such as having a property with a space like
"one two"
.
Another example where quotes do matter is when using numeric literals as property keys:
var object = {
1e2: 1,
100: 2
};
This may look alright at first sight, but this code in fact throws a syntax error in ECMAScript 5 strict mode. This happens because 1e2
and 100
are coerced into strings before getting used as the property name. Both String(1e2)
and String(100)
happen to be equal to "100"
, which causes the "Duplicate data property in object literal not allowed in strict mode" error. Issues like that can be tricky to debug, so some prefer to require quotes around all property names.
Rule Details
This rule aims to enforce use of quotes in property names and as such will flag any properties that don't use quotes (default behavior).
Options
There are four behaviors for this rule: "always"
(default), "as-needed"
, "consistent"
and "consistent-as-needed"
. You can define these options in your configuration as:
{
"quote-props": ["error", "as-needed"]
}
"always"
When configured with "always"
as the first option (the default), quoting for all properties will be enforced. Some believe that ensuring property names in object literals are always wrapped in quotes is generally a good idea, since depending on the property name you may need to quote them anyway. Consider this example:
var object = {
foo: "bar",
baz: 42,
"qux-lorem": true
};
Here, the properties foo
and baz
are not wrapped in quotes, but qux-lorem
is, because it doesn’t work without the quotes. This is rather inconsistent. Instead, you may prefer to quote names of all properties:
var object = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
or, if you prefer single quotes:
var object = {
'foo': 'bar',
'baz': 42,
'qux-lorem': true
};
When configured with "always"
as the first option (the default), quoting for all properties will be enforced. The following patterns are considered problems:
/*eslint quote-props: ["error", "always"]*/
var object = {
foo: "bar",
baz: 42,
"qux-lorem": true
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "always"]*/
/*eslint-env es6*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42,
'qux-lorem': true
};
var object3 = {
foo() {
return;
}
};
"as-needed"
When configured with "as-needed"
as the first option, quotes will be enforced when they are strictly required, and unnecessary quotes will cause warnings. The following patterns are considered problems:
/*eslint quote-props: ["error", "as-needed"]*/
var object = {
"a": 0,
"0": 0,
"true": 0,
"null": 0
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "as-needed"]*/
/*eslint-env es6*/
var object1 = {
"a-b": 0,
"0x0": 0,
"1e2": 0
};
var object2 = {
foo: 'bar',
baz: 42,
true: 0,
0: 0,
'qux-lorem': true
};
var object3 = {
foo() {
return;
}
};
When the "as-needed"
mode is selected, an additional keywords
option can be provided. This flag indicates whether language keywords should be quoted as properties. By default it is set to false
.
{
"quote-props": ["error", "as-needed", { "keywords": true }]
}
When keywords
is set to true
, the following patterns become problems:
/*eslint quote-props: ["error", "as-needed", { "keywords": true }]*/
var x = {
while: 1,
volatile: "foo"
};
Another modifier for this rule is the unnecessary
option which defaults to true
. Setting this to false
will prevent the rule from complaining about unnecessarily quoted properties. This comes in handy when you only care about quoting keywords.
{
"quote-props": ["error", "as-needed", { "keywords": true, "unnecessary": false }]
}
When unnecessary
is set to false
, the following patterns stop being problems:
/*eslint quote-props: ["error", "as-needed", { "keywords": true, "unnecessary": false }]*/
var x = {
"while": 1,
"foo": "bar" // Would normally have caused a warning
};
A numbers
flag, with default value false
, can also be used as a modifier for the "as-needed"
mode. When it is set to true
, numeric literals should always be quoted.
{
"quote-props": ["error", "as-needed", {"numbers": true}]
}
When numbers
is set to true
, the following patterns become problems:
/*eslint quote-props: ["error", "as-needed", { "numbers": true }]*/
var x = {
100: 1
}
and the following patterns stop being problems:
var x = {
"100": 1
}
"consistent"
When configured with "consistent"
, the patterns below are considered problems. Basically "consistent"
means all or no properties are expected to be quoted, in other words quoting style can't be mixed within an object. Please note the latter situation (no quotation at all) isn't always possible as some property names require quoting.
/*eslint quote-props: ["error", "consistent"]*/
var object1 = {
foo: "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
baz: 42
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "consistent"]*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42
};
var object3 = {
foo: 'bar',
baz: 42
};
"consistent-as-needed"
When configured with "consistent-as-needed"
, the behavior is similar to "consistent"
with one difference. Namely, properties' quoting should be consistent (as in "consistent"
) but whenever all quotes are redundant a warning is raised. In other words if at least one property name has to be quoted (like qux-lorem
) then all property names must be quoted, otherwise no properties can be quoted. The following patterns are considered problems:
/*eslint quote-props: ["error", "consistent-as-needed"]*/
var object1 = {
foo: "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
'foo': 'bar',
'baz': 42
};
The following patterns are not considered problems:
/*eslint quote-props: ["error", "consistent-as-needed"]*/
var object1 = {
"foo": "bar",
"baz": 42,
"qux-lorem": true
};
var object2 = {
foo: 'bar',
baz: 42
};
When the "consistent-as-needed"
mode is selected, an additional keywords
option can be provided. This flag indicates whether language keywords can be used unquoted as properties. By default it is set to false
.
{
"quote-props": ["error", "consistent-as-needed", { "keywords": true }]
}
When keywords
is set to true
, the following patterns are considered problems:
/*eslint quote-props: ["error", "consistent-as-needed", { "keywords": true }]*/
var x = {
while: 1,
volatile: "foo"
};
When Not To Use It
If you don't care if property names are consistently wrapped in quotes or not, and you don't target legacy ES3 environments, turn this rule off.
Further Reading
Missing semicolon. Open
})
- Read upRead up
- Exclude checks
Enforce or Disallow Semicolons (semi)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
JavaScript is unique amongst the C-like languages in that it doesn't require semicolons at the end of each statement. In many cases, the JavaScript engine can determine that a semicolon should be in a certain spot and will automatically add it. This feature is known as automatic semicolon insertion (ASI) and is considered one of the more controversial features of JavaScript. For example, the following lines are both valid:
var name = "ESLint"
var website = "eslint.org";
On the first line, the JavaScript engine will automatically insert a semicolon, so this is not considered a syntax error. The JavaScript engine still knows how to interpret the line and knows that the line end indicates the end of the statement.
In the debate over ASI, there are generally two schools of thought. The first is that we should treat ASI as if it didn't exist and always include semicolons manually. The rationale is that it's easier to always include semicolons than to try to remember when they are or are not required, and thus decreases the possibility of introducing an error.
However, the ASI mechanism can sometimes be tricky to people who are using semicolons. For example, consider this code:
return
{
name: "ESLint"
};
This may look like a return
statement that returns an object literal, however, the JavaScript engine will interpret this code as:
return;
{
name: "ESLint";
}
Effectively, a semicolon is inserted after the return
statement, causing the code below it (a labeled literal inside a block) to be unreachable. This rule and the [no-unreachable](no-unreachable.md) rule will protect your code from such cases.
On the other side of the argument are those who says that since semicolons are inserted automatically, they are optional and do not need to be inserted manually. However, the ASI mechanism can also be tricky to people who don't use semicolons. For example, consider this code:
var globalCounter = { }
(function () {
var n = 0
globalCounter.increment = function () {
return ++n
}
})()
In this example, a semicolon will not be inserted after the first line, causing a run-time error (because an empty object is called as if it's a function). The [no-unexpected-multiline](no-unexpected-multiline.md) rule can protect your code from such cases.
Although ASI allows for more freedom over your coding style, it can also make your code behave in an unexpected way, whether you use semicolons or not. Therefore, it is best to know when ASI takes place and when it does not, and have ESLint protect your code from these potentially unexpected cases. In short, as once described by Isaac Schlueter, a \n
character always ends a statement (just like a semicolon) unless one of the following is true:
- The statement has an unclosed paren, array literal, or object literal or ends in some other way that is not a valid way to end a statement. (For instance, ending with
.
or,
.) - The line is
--
or++
(in which case it will decrement/increment the next token.) - It is a
for()
,while()
,do
,if()
, orelse
, and there is no{
- The next line starts with
[
,(
,+
,*
,/
,-
,,
,.
, or some other binary operator that can only be found between two tokens in a single expression.
Rule Details
This rule is aimed at ensuring consistent use of semicolons. You can decide whether or not to require semicolons at the end of statements.
Options
The rule takes one or two options. The first one is a string, which could be "always"
or "never"
. The default is "always"
. The second one is an object for more fine-grained configuration when the first option is "always"
.
You can set the option in configuration like this:
"always"
By using the default option, semicolons must be used any place where they are valid.
semi: ["error", "always"]
The following patterns are considered problems:
/*eslint semi: "error"*/
var name = "ESLint"
object.method = function() {
// ...
}
The following patterns are not considered problems:
/*eslint semi: "error"*/
var name = "ESLint";
object.method = function() {
// ...
};
Fine-grained control
When setting the first option as "always", an additional option can be added to omit the last semicolon in a one-line block, that is, a block in which its braces (and therefore the content of the block) are in the same line:
semi: ["error", "always", { "omitLastInOneLineBlock": true}]
The following patterns are considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) {
bar()
}
if (foo) { bar(); }
The following patterns are not considered problems:
/*eslint semi: ["error", "always", { "omitLastInOneLineBlock": true}] */
if (foo) { bar() }
if (foo) { bar(); baz() }
"never"
If you want to enforce that semicolons are never used, switch the configuration to:
semi: [2, "never"]
Then, the following patterns are considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint";
object.method = function() {
// ...
};
And the following patterns are not considered problems:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
object.method = function() {
// ...
}
Even in "never"
mode, semicolons are still allowed to disambiguate statements beginning with [
, (
, /
, +
, or -
:
/*eslint semi: ["error", "never"]*/
var name = "ESLint"
;(function() {
// ...
})()
When Not To Use It
If you do not want to enforce semicolon usage (or omission) in any particular way, then you can turn this rule off.
Further Reading
- An Open Letter to JavaScript Leaders Regarding Semicolons
- JavaScript Semicolon Insertion
- Understanding Automatic Semicolon Insertion in JavaScript
Related Rules
- [no-extra-semi](no-extra-semi.md)
- [no-unexpected-multiline](no-unexpected-multiline.md)
- [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/
Line 580 exceeds the maximum line length of 80. Open
return Object.keys(data_.groups.group_mapping.studyMap).reduce(function(a, b) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 730 exceeds the maximum line length of 80. Open
QueryByGeneUtil. query (cohortIdsList ? cohortIdsList: window.cohortIdsList, this.stat(),
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Infix operators must be spaced. Open
QueryByGeneUtil. query (cohortIdsList ? cohortIdsList: window.cohortIdsList, this.stat(),
- Read upRead up
- Exclude checks
Require Spaces Around Infix Operators (space-infix-ops)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;
The proponents of these extra spaces believe it make the code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;
While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details
This rule is aimed at ensuring there are spaces around infix operators.
Options
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", {"int32Hint": false}]
int32Hint
Set the int32Hint
option to true
(default is false
) to allow write a|0
without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integer
The following patterns are considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {a=0}=bar;
function foo(a=0) { }
The following patterns are not considered problems:
/*eslint space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a + b
a ? b : c
const a = {b:1};
var {a = 0} = bar;
function foo(a = 0) { }
Source: http://eslint.org/docs/rules/
Expected indentation of 14 space characters but found 12. Open
break;
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 488 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseIdIndex].cna_details.push(_cnaMetaIndex);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 666 exceeds the maximum line length of 80. Open
$.when(this.fetchCompleteData('patient', true), this.fetchCompleteData('sample', true)).then(function() {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 782 exceeds the maximum line length of 80. Open
_.map(self.getStudyCacseIdsUsingUIDs('sample', filters_[attributes.attr_id]), function(item) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 411 exceeds the maximum line length of 80. Open
_mutGeneMeta[_uniqueId].qval = (window.iviz.datamanager.getCancerStudyIds().length === 1 && _mutGeneDataObj.hasOwnProperty('qval')) ? _mutGeneDataObj.qval : null;
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Expected indentation of 14 space characters but found 12. Open
break;
- Read upRead up
- Exclude checks
enforce consistent indentation (indent)
(fixable) The --fix
option on the [command line](../user-guide/command-line-interface#fix) automatically fixes problems reported by this rule.
There are several common guidelines which require specific indentation of nested blocks and statements, like:
function hello(indentSize, type) {
if (indentSize === 4 && type !== 'tab') {
console.log('Each next indentation will increase on 4 spaces');
}
}
These are the most common scenarios recommended in different style guides:
- Two spaces, not longer and no tabs: Google, npm, Node.js, Idiomatic, Felix
- Tabs: jQuery
- Four spaces: Crockford
Rule Details
This rule enforces a consistent indentation style. The default style is 4 spaces
.
Options
This rule has a mixed option:
For example, for 2-space indentation:
{
"indent": ["error", 2]
}
Or for tabbed indentation:
{
"indent": ["error", "tab"]
}
Examples of incorrect code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the default options:
/*eslint indent: "error"*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
This rule has an object option:
-
"SwitchCase"
(default: 0) enforces indentation level forcase
clauses inswitch
statements -
"VariableDeclarator"
(default: 1) enforces indentation level forvar
declarators; can also take an object to define separate rules forvar
,let
andconst
declarations.
Level of indentation denotes the multiple of the indent specified. Example:
- Indent of 4 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 8 spaces. - Indent of 2 spaces with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 4 spaces. - Indent of 2 spaces with
VariableDeclarator
set to{"var": 2, "let": 2, "const": 3}
will indent the multi-line variable declarations with 4 spaces forvar
andlet
, 6 spaces forconst
statements. - Indent of tab with
VariableDeclarator
set to2
will indent the multi-line variable declarations with 2 tabs. - Indent of 2 spaces with
SwitchCase
set to0
will not indentcase
clauses with respect toswitch
statements. - Indent of 2 spaces with
SwitchCase
set to2
will indentcase
clauses with 4 spaces with respect toswitch
statements. - Indent of tabs with
SwitchCase
set to2
will indentcase
clauses with 2 tabs with respect toswitch
statements.
tab
Examples of incorrect code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
b=c;
function foo(d) {
e=f;
}
}
Examples of correct code for this rule with the "tab"
option:
/*eslint indent: ["error", "tab"]*/
if (a) {
/*tab*/b=c;
/*tab*/function foo(d) {
/*tab*//*tab*/e=f;
/*tab*/}
}
SwitchCase
Examples of incorrect code for this rule with the 2, { "SwitchCase": 1 }
options:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
Examples of correct code for this rule with the 2, { "SwitchCase": 1 }
option:
/*eslint indent: ["error", 2, { "SwitchCase": 1 }]*/
switch(a){
case "a":
break;
case "b":
break;
}
VariableDeclarator
Examples of incorrect code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 1 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 1 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": 2 }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": 2 }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Examples of correct code for this rule with the 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }
options:
/*eslint indent: ["error", 2, { "VariableDeclarator": { "var": 2, "let": 2, "const": 3 } }]*/
/*eslint-env es6*/
var a,
b,
c;
let a,
b,
c;
const a = 1,
b = 2,
c = 3;
Compatibility
-
JSHint:
indent
-
JSCS:
validateIndentation
Source: http://eslint.org/docs/rules/
Line 416 exceeds the maximum line length of 80. Open
data_.groups.sample.data[_caseUIdIndex].mutated_genes.push(_mutGeneMetaIndex);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 479 exceeds the maximum line length of 80. Open
if ((window.iviz.datamanager.getCancerStudyIds().length !== 1) || _cnaDataPerStudy.gistic[_index] === null) {
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/
Line 753 exceeds the maximum line length of 80. Open
var _patientId = self.getPatientId(_caseDataObj.study_id, _caseDataObj.sample_id);
- Read upRead up
- Exclude checks
enforce a maximum line length (max-len)
Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long
Rule Details
This rule enforces a maximum line length to increase code readability and maintainability.
Note: This rule calculates the length of a line via code points, not characters. That means if you use a double-byte character in your code, it will count as 2 code points instead of 1, and 2 will be used to calculate line length. This is a technical limitation of JavaScript that is made easier with ES2015, and we will look to update this when ES2015 is available in Node.js.
Options
This rule has a number or object option:
-
"code"
(default80
) enforces a maximum line length -
"tabWidth"
(default4
) specifies the character width for tab characters -
"comments"
enforces a maximum line length for comments; defaults to value ofcode
-
"ignorePattern"
ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON -
"ignoreComments": true
ignores all trailing comments and comments on their own line -
"ignoreTrailingComments": true
ignores only trailing comments -
"ignoreUrls": true
ignores lines that contain a URL
code
Examples of incorrect code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
Examples of correct code for this rule with the default { "code": 80 }
option:
/*eslint max-len: ["error", 80]*/
var foo = {
"bar": "This is a bar.",
"baz": { "qux": "This is a qux" },
"easier": "to read"
};
tabWidth
Examples of incorrect code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
Examples of correct code for this rule with the default { "tabWidth": 4 }
option:
/*eslint max-len: ["error", 80, 4]*/
\t \t var foo = {
\t \t \t \t "bar": "This is a bar.",
\t \t \t \t "baz": { "qux": "This is a qux" }
\t \t };
comments
Examples of incorrect code for this rule with the { "comments": 65 }
option:
/*eslint max-len: ["error", { "comments": 65 }]*/
/**
* This is a comment that violates the maximum line length we have specified
**/
ignoreComments
Examples of correct code for this rule with the { "ignoreComments": true }
option:
/*eslint max-len: ["error", { "ignoreComments": true }]*/
/**
* This is a really really really really really really really really really long comment
**/
ignoreTrailingComments
Examples of correct code for this rule with the { "ignoreTrailingComments": true }
option:
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/
var foo = 'bar'; // This is a really really really really really really really long comment
ignoreUrls
Examples of correct code for this rule with the { "ignoreUrls": true }
option:
/*eslint max-len: ["error", { "ignoreUrls": true }]*/
var url = 'https://www.example.com/really/really/really/really/really/really/really/long';
ignorePattern
Examples of correct code for this rule with the { "ignorePattern": true }
option:
/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/
var dep = require('really/really/really/really/really/really/really/really/long/module');
Related Rules
- [complexity](complexity.md)
- [max-depth](max-depth.md)
- [max-nested-callbacks](max-nested-callbacks.md)
- [max-params](max-params.md)
- [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/