norm_pct = this.normalized_percentage(value, settings.start, settings.end),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        handle_offset = -handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                slider.foundation("slider", "set_value", $(this).val());

Close

enforce the consistent use of either backticks, double, or single quotes (quotes)

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 enforces the consistent use of either backticks, double, or single quotes.

Options

This rule has two options, a string option and an object option.

String option:

• "double" (default) requires the use of double quotes wherever possible
• "single" requires the use of single quotes wherever possible
• "backtick" requires the use of backticks wherever possible

Object option:

• "avoidEscape": true allows strings to use single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise
• "allowTemplateLiterals": true allows strings to use backticks

Deprecated: The object property avoid-escape is deprecated; please use the object property avoidEscape instead.

double

Examples of incorrect code for this rule with the default "double" option:

/*eslint quotes: ["error", "double"]*/

var single = 'single';
var unescaped = 'a string containing "double" quotes';

Examples of correct code for this rule with the default "double" option:

/*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

single

Examples of incorrect code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/

var double = "double";
var unescaped = "a string containing 'single' quotes";

Examples of correct code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/

var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution

backticks

Examples of incorrect code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/

var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';

Examples of correct code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/

var backtick = `backtick`;

avoidEscape

Examples of additional correct code for this rule with the "double", { "avoidEscape": true } options:

/*eslint quotes: ["error", "double", { "avoidEscape": true }]*/

var single = 'a string containing "double" quotes';

Examples of additional correct code for this rule with the "single", { "avoidEscape": true } options:

/*eslint quotes: ["error", "single", { "avoidEscape": true }]*/

var double = "a string containing 'single' quotes";

Examples of additional correct code for this rule with the "backtick", { "avoidEscape": true } options:

/*eslint quotes: ["error", "backtick", { "avoidEscape": true }]*/

var double = "a string containing `backtick` quotes"

allowTemplateLiterals

Examples of additional correct code for this rule with the "double", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "double", { "allowTemplateLiterals": true }]*/

var double = "double";
var double = `double`;

Examples of additional correct code for this rule with the "single", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "single", { "allowTemplateLiterals": true }]*/

var single = 'single';
var single = `single`;

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/

          handle_offset = norm_pct * (bar_l - handle_l) - 1,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

    calculate_position : function ($handle, cursor_x) {

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          bar_o = $.data($handle[0], 'bar_o');

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((bar_o + bar_l - cursor_x) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          handle_offset = norm_pct * (bar_l - handle_l) - 1,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        $handle.siblings('.range-slider-active-segment').css('width', progress_bar_length + '%');

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                  scroll_offset = window.scrollY;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          bar_l = $.data($handle[0], 'bar_l'),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                scroll_offset = window.scrollY;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                slider.foundation("slider", "set_value", $(this).val());

Close

enforce the consistent use of either backticks, double, or single quotes (quotes)

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 enforces the consistent use of either backticks, double, or single quotes.

Options

This rule has two options, a string option and an object option.

String option:

• "double" (default) requires the use of double quotes wherever possible
• "single" requires the use of single quotes wherever possible
• "backtick" requires the use of backticks wherever possible

Object option:

• "avoidEscape": true allows strings to use single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise
• "allowTemplateLiterals": true allows strings to use backticks

Deprecated: The object property avoid-escape is deprecated; please use the object property avoidEscape instead.

double

Examples of incorrect code for this rule with the default "double" option:

/*eslint quotes: ["error", "double"]*/

var single = 'single';
var unescaped = 'a string containing "double" quotes';

Examples of correct code for this rule with the default "double" option:

/*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

single

Examples of incorrect code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/

var double = "double";
var unescaped = "a string containing 'single' quotes";

Examples of correct code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/

var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution

backticks

Examples of incorrect code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/

var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';

Examples of correct code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/

var backtick = `backtick`;

avoidEscape

Examples of additional correct code for this rule with the "double", { "avoidEscape": true } options:

/*eslint quotes: ["error", "double", { "avoidEscape": true }]*/

var single = 'a string containing "double" quotes';

Examples of additional correct code for this rule with the "single", { "avoidEscape": true } options:

/*eslint quotes: ["error", "single", { "avoidEscape": true }]*/

var double = "a string containing 'single' quotes";

Examples of additional correct code for this rule with the "backtick", { "avoidEscape": true } options:

/*eslint quotes: ["error", "backtick", { "avoidEscape": true }]*/

var double = "a string containing `backtick` quotes"

allowTemplateLiterals

Examples of additional correct code for this rule with the "double", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "double", { "allowTemplateLiterals": true }]*/

var double = "double";
var double = `double`;

Examples of additional correct code for this rule with the "single", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "single", { "allowTemplateLiterals": true }]*/

var single = 'single';
var single = `single`;

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/

          $hidden_inputs = $handle.parent().children('input[type=hidden]');

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      handle_offset = settings.vertical ? -handle_offset + bar_l - handle_l + 1 : handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        $handle.siblings('.range-slider-active-segment').css('height', progress_bar_length + '%');

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          progress_bar_length = norm_pct * 100,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          $handle_parent = $handle.parent(),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        decimal_places_match_result = ('' + settings.step).match(/\.([\d]*)/);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((cursor_x - bar_o) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          handle_l = $.data($handle[0], 'handle_l'),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      self.S('[' + this.attr_name() + ']').each(function () {

Close

require constructor names to begin with a capital letter (new-cap)

The new operator in JavaScript creates a new instance of a particular type of object. That type of object is represented by a constructor function. Since constructor functions are just regular functions, the only defining characteristic is that new is being used as part of the call. Native JavaScript functions begin with an uppercase letter to distinguish those functions that are to be used as constructors from functions that are not. Many style guides recommend following this pattern to more easily determine which functions are to be used as constructors.

var friend = new Person();

Rule Details

This rule requires constructor names to begin with a capital letter. Certain built-in identifiers are exempt from this rule. These identifiers are:

• Array
• Boolean
• Date
• Error
• Function
• Number
• Object
• RegExp
• String
• Symbol

Examples of correct code for this rule:

/*eslint new-cap: "error"*/

function foo(arg) {
    return Boolean(arg);
}

Options

This rule has an object option:

• "newIsCap": true (default) requires all new operators to be called with uppercase-started functions.
• "newIsCap": false allows new operators to be called with lowercase-started or uppercase-started functions.
• "capIsNew": true (default) requires all uppercase-started functions to be called with new operators.
• "capIsNew": false allows uppercase-started functions to be called without new operators.
• "newIsCapExceptions" allows specified lowercase-started function names to be called with the new operator.
• "newIsCapExceptionPattern" allows any lowercase-started function names that match the specified regex pattern to be called with the new operator.
• "capIsNewExceptions" allows specified uppercase-started function names to be called without the new operator.
• "capIsNewExceptionPattern" allows any uppercase-started function names that match the specified regex pattern to be called without the new operator.
• "properties": true (default) enables checks on object properties
• "properties": false disables checks on object properties

newIsCap

Examples of incorrect code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new person();

Examples of correct code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new Person();

Examples of correct code for this rule with the { "newIsCap": false } option:

/*eslint new-cap: ["error", { "newIsCap": false }]*/

var friend = new person();

capIsNew

Examples of incorrect code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = Person();

Examples of correct code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = new Person();

Examples of correct code for this rule with the { "capIsNew": false } option:

/*eslint new-cap: ["error", { "capIsNew": false }]*/

var colleague = Person();

newIsCapExceptions

Examples of additional correct code for this rule with the { "newIsCapExceptions": ["events"] } option:

/*eslint new-cap: ["error", { "newIsCapExceptions": ["events"] }]*/

var events = require('events');

var emitter = new events();

newIsCapExceptionPattern

Examples of additional correct code for this rule with the { "newIsCapExceptionPattern": "^person\.." } option:

/*eslint new-cap: ["error", { "newIsCapExceptionPattern": "^person\.." }]*/

var friend = new person.acquaintance();
var bestFriend = new person.friend();

capIsNewExceptions

Examples of additional correct code for this rule with the { "capIsNewExceptions": ["Person"] } option:

/*eslint new-cap: ["error", { "capIsNewExceptions": ["Person"] }]*/

function foo(arg) {
    return Person(arg);
}

capIsNewExceptionPattern

Examples of additional correct code for this rule with the { "capIsNewExceptionPattern": "^Person\.." } option:

/*eslint new-cap: ["error", { "capIsNewExceptionPattern": "^Person\.." }]*/

var friend = person.Acquaintance();
var bestFriend = person.Friend();

properties

Examples of incorrect code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.acquaintance();

Examples of correct code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.Acquaintance();

Examples of correct code for this rule with the { "properties": false } option:

/*eslint new-cap: ["error", { "properties": false }]*/

var friend = new person.acquaintance();

When Not To Use It

If you have conventions that don't require an uppercase letter for constructors, or don't require capitalized functions be only used as constructors, turn this rule off. Source: http://eslint.org/docs/rules/

          handle_offset = norm_pct * (bar_l - handle_l) - 1,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      this.S('[' + this.attr_name() + ']').each(function () {

Close

require constructor names to begin with a capital letter (new-cap)

The new operator in JavaScript creates a new instance of a particular type of object. That type of object is represented by a constructor function. Since constructor functions are just regular functions, the only defining characteristic is that new is being used as part of the call. Native JavaScript functions begin with an uppercase letter to distinguish those functions that are to be used as constructors from functions that are not. Many style guides recommend following this pattern to more easily determine which functions are to be used as constructors.

var friend = new Person();

Rule Details

This rule requires constructor names to begin with a capital letter. Certain built-in identifiers are exempt from this rule. These identifiers are:

• Array
• Boolean
• Date
• Error
• Function
• Number
• Object
• RegExp
• String
• Symbol

Examples of correct code for this rule:

/*eslint new-cap: "error"*/

function foo(arg) {
    return Boolean(arg);
}

Options

This rule has an object option:

• "newIsCap": true (default) requires all new operators to be called with uppercase-started functions.
• "newIsCap": false allows new operators to be called with lowercase-started or uppercase-started functions.
• "capIsNew": true (default) requires all uppercase-started functions to be called with new operators.
• "capIsNew": false allows uppercase-started functions to be called without new operators.
• "newIsCapExceptions" allows specified lowercase-started function names to be called with the new operator.
• "newIsCapExceptionPattern" allows any lowercase-started function names that match the specified regex pattern to be called with the new operator.
• "capIsNewExceptions" allows specified uppercase-started function names to be called without the new operator.
• "capIsNewExceptionPattern" allows any uppercase-started function names that match the specified regex pattern to be called without the new operator.
• "properties": true (default) enables checks on object properties
• "properties": false disables checks on object properties

newIsCap

Examples of incorrect code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new person();

Examples of correct code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new Person();

Examples of correct code for this rule with the { "newIsCap": false } option:

/*eslint new-cap: ["error", { "newIsCap": false }]*/

var friend = new person();

capIsNew

Examples of incorrect code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = Person();

Examples of correct code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = new Person();

Examples of correct code for this rule with the { "capIsNew": false } option:

/*eslint new-cap: ["error", { "capIsNew": false }]*/

var colleague = Person();

newIsCapExceptions

Examples of additional correct code for this rule with the { "newIsCapExceptions": ["events"] } option:

/*eslint new-cap: ["error", { "newIsCapExceptions": ["events"] }]*/

var events = require('events');

var emitter = new events();

newIsCapExceptionPattern

Examples of additional correct code for this rule with the { "newIsCapExceptionPattern": "^person\.." } option:

/*eslint new-cap: ["error", { "newIsCapExceptionPattern": "^person\.." }]*/

var friend = new person.acquaintance();
var bestFriend = new person.friend();

capIsNewExceptions

Examples of additional correct code for this rule with the { "capIsNewExceptions": ["Person"] } option:

/*eslint new-cap: ["error", { "capIsNewExceptions": ["Person"] }]*/

function foo(arg) {
    return Person(arg);
}

capIsNewExceptionPattern

Examples of additional correct code for this rule with the { "capIsNewExceptionPattern": "^Person\.." } option:

/*eslint new-cap: ["error", { "capIsNewExceptionPattern": "^Person\.." }]*/

var friend = person.Acquaintance();
var bestFriend = person.Friend();

properties

Examples of incorrect code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.acquaintance();

Examples of correct code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.Acquaintance();

Examples of correct code for this rule with the { "properties": false } option:

/*eslint new-cap: ["error", { "properties": false }]*/

var friend = new person.acquaintance();

When Not To Use It

If you have conventions that don't require an uppercase letter for constructors, or don't require capitalized functions be only used as constructors, turn this rule off. Source: http://eslint.org/docs/rules/

          bar_l = $.data($handle[0], 'bar_l'),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((bar_o + bar_l - cursor_x) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        handle_offset = -handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      handle_offset = settings.vertical ? -handle_offset + bar_l - handle_l + 1 : handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      handle_offset = settings.vertical ? -handle_offset + bar_l - handle_l + 1 : handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      handle_offset = settings.vertical ? -handle_offset + bar_l - handle_l + 1 : handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      self.S(window)

Close

require constructor names to begin with a capital letter (new-cap)

The new operator in JavaScript creates a new instance of a particular type of object. That type of object is represented by a constructor function. Since constructor functions are just regular functions, the only defining characteristic is that new is being used as part of the call. Native JavaScript functions begin with an uppercase letter to distinguish those functions that are to be used as constructors from functions that are not. Many style guides recommend following this pattern to more easily determine which functions are to be used as constructors.

var friend = new Person();

Rule Details

This rule requires constructor names to begin with a capital letter. Certain built-in identifiers are exempt from this rule. These identifiers are:

• Array
• Boolean
• Date
• Error
• Function
• Number
• Object
• RegExp
• String
• Symbol

Examples of correct code for this rule:

/*eslint new-cap: "error"*/

function foo(arg) {
    return Boolean(arg);
}

Options

This rule has an object option:

• "newIsCap": true (default) requires all new operators to be called with uppercase-started functions.
• "newIsCap": false allows new operators to be called with lowercase-started or uppercase-started functions.
• "capIsNew": true (default) requires all uppercase-started functions to be called with new operators.
• "capIsNew": false allows uppercase-started functions to be called without new operators.
• "newIsCapExceptions" allows specified lowercase-started function names to be called with the new operator.
• "newIsCapExceptionPattern" allows any lowercase-started function names that match the specified regex pattern to be called with the new operator.
• "capIsNewExceptions" allows specified uppercase-started function names to be called without the new operator.
• "capIsNewExceptionPattern" allows any uppercase-started function names that match the specified regex pattern to be called without the new operator.
• "properties": true (default) enables checks on object properties
• "properties": false disables checks on object properties

newIsCap

Examples of incorrect code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new person();

Examples of correct code for this rule with the default { "newIsCap": true } option:

/*eslint new-cap: ["error", { "newIsCap": true }]*/

var friend = new Person();

Examples of correct code for this rule with the { "newIsCap": false } option:

/*eslint new-cap: ["error", { "newIsCap": false }]*/

var friend = new person();

capIsNew

Examples of incorrect code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = Person();

Examples of correct code for this rule with the default { "capIsNew": true } option:

/*eslint new-cap: ["error", { "capIsNew": true }]*/

var colleague = new Person();

Examples of correct code for this rule with the { "capIsNew": false } option:

/*eslint new-cap: ["error", { "capIsNew": false }]*/

var colleague = Person();

newIsCapExceptions

Examples of additional correct code for this rule with the { "newIsCapExceptions": ["events"] } option:

/*eslint new-cap: ["error", { "newIsCapExceptions": ["events"] }]*/

var events = require('events');

var emitter = new events();

newIsCapExceptionPattern

Examples of additional correct code for this rule with the { "newIsCapExceptionPattern": "^person\.." } option:

/*eslint new-cap: ["error", { "newIsCapExceptionPattern": "^person\.." }]*/

var friend = new person.acquaintance();
var bestFriend = new person.friend();

capIsNewExceptions

Examples of additional correct code for this rule with the { "capIsNewExceptions": ["Person"] } option:

/*eslint new-cap: ["error", { "capIsNewExceptions": ["Person"] }]*/

function foo(arg) {
    return Person(arg);
}

capIsNewExceptionPattern

Examples of additional correct code for this rule with the { "capIsNewExceptionPattern": "^Person\.." } option:

/*eslint new-cap: ["error", { "capIsNewExceptionPattern": "^Person\.." }]*/

var friend = person.Acquaintance();
var bestFriend = person.Friend();

properties

Examples of incorrect code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.acquaintance();

Examples of correct code for this rule with the default { "properties": true } option:

/*eslint new-cap: ["error", { "properties": true }]*/

var friend = new person.Acquaintance();

Examples of correct code for this rule with the { "properties": false } option:

/*eslint new-cap: ["error", { "properties": false }]*/

var friend = new person.acquaintance();

When Not To Use It

If you have conventions that don't require an uppercase letter for constructors, or don't require capitalized functions be only used as constructors, turn this rule off. Source: http://eslint.org/docs/rules/

          handle_l = $.data($handle[0], 'handle_l'),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          handle_o = $.data($handle[0], 'handle_o'),

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((bar_o + bar_l - cursor_x) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          handle_offset = norm_pct * (bar_l - handle_l) - 1,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

      handle_offset = settings.vertical ? -handle_offset + bar_l - handle_l + 1 : handle_offset;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          $hidden_inputs.trigger('change.fndtn.slider');

Close

enforce consistent indentation (indent)

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 for case clauses in switch statements
• "VariableDeclarator" (default: 1) enforces indentation level for var declarators; can also take an object to define separate rules for var, let and const declarations.
• "outerIIFEBody" (default: 1) enforces indentation level for file-level IIFEs.
• "MemberExpression" (off by default) enforces indentation level for multi-line property chains (except in variable declarations and assignments)
• "FunctionDeclaration" takes an object to define rules for function declarations.
  • parameters (off by default) enforces indentation level for parameters in a function declaration. This can either be a number indicating indentation level, or the string "first" indicating that all parameters of the declaration must be aligned with the first parameter.
  • body (default: 1) enforces indentation level for the body of a function declaration.
• "FunctionExpression" takes an object to define rules for function expressions.
  • parameters (off by default) enforces indentation level for parameters in a function expression. This can either be a number indicating indentation level, or the string "first" indicating that all parameters of the expression must be aligned with the first parameter.
  • body (default: 1) enforces indentation level for the body of a function expression.
• "CallExpression" takes an object to define rules for function call expressions.
  • arguments (off by default) enforces indentation level for arguments in a call expression. This can either be a number indicating indentation level, or the string "first" indicating that all arguments of the expression must be aligned with the first argument.
• "ArrayExpression" (default: 1) enforces indentation level for elements in arrays. It can also be set to the string "first", indicating that all the elements in the array should be aligned with the first element.
• "ObjectExpression" (default: 1) enforces indentation level for properties in objects. It can be set to the string "first", indicating that all properties in the object should be aligned with the first property.

Level of indentation denotes the multiple of the indent specified. Example:

• Indent of 4 spaces with VariableDeclarator set to 2 will indent the multi-line variable declarations with 8 spaces.
• Indent of 2 spaces with VariableDeclarator set to 2 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 for var and let, 6 spaces for const statements.
• Indent of tab with VariableDeclarator set to 2 will indent the multi-line variable declarations with 2 tabs.
• Indent of 2 spaces with SwitchCase set to 0 will not indent case clauses with respect to switch statements.
• Indent of 2 spaces with SwitchCase set to 1 will indent case clauses with 2 spaces with respect to switch statements.
• Indent of 2 spaces with SwitchCase set to 2 will indent case clauses with 4 spaces with respect to switch statements.
• Indent of tab with SwitchCase set to 2 will indent case clauses with 2 tabs with respect to switch statements.
• Indent of 2 spaces with MemberExpression set to 0 will indent the multi-line property chains with 0 spaces.
• Indent of 2 spaces with MemberExpression set to 1 will indent the multi-line property chains with 2 spaces.
• Indent of 2 spaces with MemberExpression set to 2 will indent the multi-line property chains with 4 spaces.
• Indent of 4 spaces with MemberExpression set to 0 will indent the multi-line property chains with 0 spaces.
• Indent of 4 spaces with MemberExpression set to 1 will indent the multi-line property chains with 4 spaces.
• Indent of 4 spaces with MemberExpression set to 2 will indent the multi-line property chains with 8 spaces.

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;

outerIIFEBody

Examples of incorrect code for this rule with the options 2, { "outerIIFEBody": 0 }:

/*eslint indent: ["error", 2, { "outerIIFEBody": 0 }]*/

(function() {

  function foo(x) {
    return x + 1;
  }

})();


if(y) {
console.log('foo');
}

Examples of correct code for this rule with the options 2, {"outerIIFEBody": 0}:

/*eslint indent: ["error", 2, { "outerIIFEBody": 0 }]*/

(function() {

function foo(x) {
  return x + 1;
}

})();


if(y) {
   console.log('foo');
}

MemberExpression

Examples of incorrect code for this rule with the 2, { "MemberExpression": 1 } options:

/*eslint indent: ["error", 2, { "MemberExpression": 1 }]*/

foo
.bar
.baz()

Examples of correct code for this rule with the 2, { "MemberExpression": 1 } option:

/*eslint indent: ["error", 2, { "MemberExpression": 1 }]*/

foo
  .bar
  .baz();

// Any indentation is permitted in variable declarations and assignments.
var bip = aardvark.badger
                  .coyote;

FunctionDeclaration

Examples of incorrect code for this rule with the 2, { "FunctionDeclaration": {"body": 1, "parameters": 2} } option:

/*eslint indent: ["error", 2, { "FunctionDeclaration": {"body": 1, "parameters": 2} }]*/

function foo(bar,
  baz,
  qux) {
    qux();
}

Examples of correct code for this rule with the 2, { "FunctionDeclaration": {"body": 1, "parameters": 2} } option:

/*eslint indent: ["error", 2, { "FunctionDeclaration": {"body": 1, "parameters": 2} }]*/

function foo(bar,
    baz,
    qux) {
  qux();
}

Examples of incorrect code for this rule with the 2, { "FunctionDeclaration": {"parameters": "first"} } option:

/*eslint indent: ["error", 2, {"FunctionDeclaration": {"parameters": "first"}}]*/

function foo(bar, baz,
  qux, boop) {
  qux();
}

Examples of correct code for this rule with the 2, { "FunctionDeclaration": {"parameters": "first"} } option:

/*eslint indent: ["error", 2, {"FunctionDeclaration": {"parameters": "first"}}]*/

function foo(bar, baz,
             qux, boop) {
  qux();
}

FunctionExpression

Examples of incorrect code for this rule with the 2, { "FunctionExpression": {"body": 1, "parameters": 2} } option:

/*eslint indent: ["error", 2, { "FunctionExpression": {"body": 1, "parameters": 2} }]*/

var foo = function(bar,
  baz,
  qux) {
    qux();
}

Examples of correct code for this rule with the 2, { "FunctionExpression": {"body": 1, "parameters": 2} } option:

/*eslint indent: ["error", 2, { "FunctionExpression": {"body": 1, "parameters": 2} }]*/

var foo = function(bar,
    baz,
    qux) {
  qux();
}

Examples of incorrect code for this rule with the 2, { "FunctionExpression": {"parameters": "first"} } option:

/*eslint indent: ["error", 2, {"FunctionExpression": {"parameters": "first"}}]*/

var foo = function(bar, baz,
  qux, boop) {
  qux();
}

Examples of correct code for this rule with the 2, { "FunctionExpression": {"parameters": "first"} } option:

/*eslint indent: ["error", 2, {"FunctionExpression": {"parameters": "first"}}]*/

var foo = function(bar, baz,
                   qux, boop) {
  qux();
}

CallExpression

Examples of incorrect code for this rule with the 2, { "CallExpression": {"arguments": 1} } option:

/*eslint indent: ["error", 2, { "CallExpression": {"arguments": 1} }]*/

foo(bar,
    baz,
      qux
);

Examples of correct code for this rule with the 2, { "CallExpression": {"arguments": 1} } option:

/*eslint indent: ["error", 2, { "CallExpression": {"arguments": 1} }]*/

foo(bar,
  baz,
  qux
);

Examples of incorrect code for this rule with the 2, { "CallExpression": {"arguments": "first"} } option:

/*eslint indent: ["error", 2, {"CallExpression": {"arguments": "first"}}]*/

foo(bar, baz,
  baz, boop, beep);

Examples of correct code for this rule with the 2, { "CallExpression": {"arguments": "first"} } option:

/*eslint indent: ["error", 2, {"CallExpression": {"arguments": "first"}}]*/

foo(bar, baz,
    baz, boop, beep);

ArrayExpression

Examples of incorrect code for this rule with the 2, { "ArrayExpression": 1 } option:

/*eslint indent: ["error", 2, { "ArrayExpression": 1 }]*/

var foo = [
    bar,
baz,
      qux
];

Examples of correct code for this rule with the 2, { "ArrayExpression": 1 } option:

/*eslint indent: ["error", 2, { "ArrayExpression": 1 }]*/

var foo = [
  bar,
  baz,
  qux
];

Examples of incorrect code for this rule with the 2, { "ArrayExpression": "first" } option:

/*eslint indent: ["error", 2, {"ArrayExpression": "first"}]*/

var foo = [bar,
  baz,
  qux
];

Examples of correct code for this rule with the 2, { "ArrayExpression": "first" } option:

/*eslint indent: ["error", 2, {"ArrayExpression": "first"}]*/

var foo = [bar,
           baz,
           qux
];

ObjectExpression

Examples of incorrect code for this rule with the 2, { "ObjectExpression": 1 } option:

/*eslint indent: ["error", 2, { "ObjectExpression": 1 }]*/

var foo = {
    bar: 1,
baz: 2,
      qux: 3
};

Examples of correct code for this rule with the 2, { "ObjectExpression": 1 } option:

/*eslint indent: ["error", 2, { "ObjectExpression": 1 }]*/

var foo = {
  bar: 1,
  baz: 2,
  qux: 3
};

Examples of incorrect code for this rule with the 2, { "ObjectExpression": "first" } option:

/*eslint indent: ["error", 2, {"ObjectExpression": "first"}]*/

var foo = { bar: 1,
  baz: 2 };

Examples of correct code for this rule with the 2, { "ObjectExpression": "first" } option:

/*eslint indent: ["error", 2, {"ObjectExpression": "first"}]*/

var foo = { bar: 1,
            baz: 2 };

Compatibility

• JSHint: indent
• JSCS: validateIndentation Source: http://eslint.org/docs/rules/

          decimal_places_match_result;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

              var scroll_offset = 0;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

              self.calculate_position(self.cache.active, self.get_cursor_position(e, 'y') + scroll_offset);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        settings.precision = decimal_places_match_result && decimal_places_match_result[1] ? decimal_places_match_result[1].length : 0;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                var scroll_offset = 0;

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

                self.calculate_position(self.cache.active, self.get_cursor_position(e, 'y') + scroll_offset);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((bar_o + bar_l - cursor_x) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((cursor_x - bar_o) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          pct = self.limit_to(((cursor_x - bar_o) / bar_l), 0, 1);

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

          progress_bar_length = norm_pct * 100,

Close

Require Camelcase (camelcase)

When it comes to naming variables, style guides generally fall into one of two camps: camelcase (variableName) and underscores (variable_name). This rule focuses on using the camelcase approach. If your style guide calls for camelcasing your variable names, then this rule is for you!

Rule Details

This rule looks for any underscores (_) located within the source code. It ignores leading and trailing underscores and only checks those in the middle of a variable name. If ESLint decides that the variable is a constant (all uppercase), then no warning will be thrown. Otherwise, a warning will be thrown. This rule only flags definitions and assignments but not function calls. In case of ES6 import statements, this rule only targets the name of the variable that will be imported into the local module scope.

Options

This rule has an object option:

• "properties": "always" (default) enforces camelcase style for property names
• "properties": "never" does not check property names

always

Examples of incorrect code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased } from "external-module"

var my_favorite_color = "#112C85";

function do_something() {
    // ...
}

obj.do_something = function() {
    // ...
};

var obj = {
    my_pref: 1
};

Examples of correct code for this rule with the default { "properties": "always" } option:

/*eslint camelcase: "error"*/

import { no_camelcased as camelCased } from "external-module";

var myFavoriteColor   = "#112C85";
var _myFavoriteColor  = "#112C85";
var myFavoriteColor_  = "#112C85";
var MY_FAVORITE_COLOR = "#112C85";
var foo = bar.baz_boom;
var foo = { qux: bar.baz_boom };

obj.do_something();
do_something();
new do_something();

var { category_id: category } = query;

never

Examples of correct code for this rule with the { "properties": "never" } option:

/*eslint camelcase: ["error", {properties: "never"}]*/

var obj = {
    my_pref: 1
};

When Not To Use It

If you have established coding standards using a different naming convention (separating words with underscores), turn this rule off. Source: http://eslint.org/docs/rules/

        .on('resize.fndtn.slider', self.throttle(function (e) {

Close

Disallow Unused Variables (no-unused-vars)

Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.

Rule Details

This rule is aimed at eliminating unused variables, functions, and parameters of functions.

A variable is considered to be used if any of the following are true:

• It represents a function that is called (doSomething())
• It is read (var y = x)
• It is passed into a function as an argument (doSomething(x))
• It is read inside of a function that is passed to another function (doSomething(function() { foo(); }))

A variable is not considered to be used if it is only ever assigned to (var x = 5) or declared.

Examples of incorrect code for this rule:

/*eslint no-unused-vars: "error"*/
/*global some_unused_var*/

// It checks variables you have defined as global
some_unused_var = 42;

var x;

// Write-only variables are not considered as used.
var y = 10;
y = 5;

// A read for a modification of itself is not considered as used.
var z = 0;
z = z + 1;

// By default, unused arguments cause warnings.
(function(foo) {
    return 5;
})();

// Unused recursive functions also cause warnings.
function fact(n) {
    if (n < 2) return 1;
    return n * fact(n - 1);
}

// When a function definition destructures an array, unused entries from the array also cause warnings.
function getY([x, y]) {
    return y;
}

Examples of correct code for this rule:

/*eslint no-unused-vars: "error"*/

var x = 10;
alert(x);

// foo is considered used here
myFunc(function foo() {
    // ...
}.bind(this));

(function(foo) {
    return foo;
})();

var myFunc;
myFunc = setTimeout(function() {
    // myFunc is considered used
    myFunc();
}, 50);

// Only the second argument from the descructured array is used.
function getY([, y]) {
    return y;
}

exported

In environments outside of CommonJS or ECMAScript modules, you may use var to create a global variable that may be used by other scripts. You can use the /* exported variableName */ comment block to indicate that this variable is being exported and therefore should not be considered unused.

Note that /* exported */ has no effect for any of the following:

• when the environment is node or commonjs
• when parserOptions.sourceType is module
• when ecmaFeatures.globalReturn is true

The line comment // exported variableName will not work as exported is not line-specific.

Examples of correct code for /* exported variableName */ operation:

/* exported global_var */

var global_var = 42;

Options

This rule takes one argument which can be a string or an object. The string settings are the same as those of the vars property (explained below).

By default this rule is enabled with all option for variables and after-used for arguments.

{
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "after-used", "ignoreRestSiblings": false }]
    }
}

vars

The vars option has two settings:

• all checks all variables for usage, including those in the global scope. This is the default setting.
• local checks only that locally-declared variables are used but will allow global variables to be unused.

vars: local

Examples of correct code for the { "vars": "local" } option:

/*eslint no-unused-vars: ["error", { "vars": "local" }]*/
/*global some_unused_var */

some_unused_var = 42;

varsIgnorePattern

The varsIgnorePattern option specifies exceptions not to check for usage: variables whose names match a regexp pattern. For example, variables whose names contain ignored or Ignored.

Examples of correct code for the { "varsIgnorePattern": "[iI]gnored" } option:

/*eslint no-unused-vars: ["error", { "varsIgnorePattern": "[iI]gnored" }]*/

var firstVarIgnored = 1;
var secondVar = 2;
console.log(secondVar);

args

The args option has three settings:

• after-used - only the last argument must be used. This allows you, for instance, to have two named parameters to a function and as long as you use the second argument, ESLint will not warn you about the first. This is the default setting.
• all - all named arguments must be used.
• none - do not check arguments.

args: after-used

Examples of incorrect code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", { "args": "after-used" }]*/

// 1 error
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

Examples of correct code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", {"args": "after-used"}]*/

(function(foo, bar, baz) {
    return baz;
})();

args: all

Examples of incorrect code for the { "args": "all" } option:

/*eslint no-unused-vars: ["error", { "args": "all" }]*/

// 2 errors
// "foo" is defined but never used
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

args: none

Examples of correct code for the { "args": "none" } option:

/*eslint no-unused-vars: ["error", { "args": "none" }]*/

(function(foo, bar, baz) {
    return bar;
})();

ignoreRestSiblings

The ignoreRestSiblings option is a boolean (default: false). Using a Rest Property it is possible to "omit" properties from an object, but by default the sibling properties are marked as "unused". With this option enabled the rest property's siblings are ignored.

Examples of correct code for the { "ignoreRestSiblings": true } option:

/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
// 'type' is ignored because it has a rest property sibling.
var { type, ...coords } = data;

argsIgnorePattern

The argsIgnorePattern option specifies exceptions not to check for usage: arguments whose names match a regexp pattern. For example, variables whose names begin with an underscore.

Examples of correct code for the { "argsIgnorePattern": "^_" } option:

/*eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }]*/

function foo(x, _y) {
    return x + 1;
}
foo();

caughtErrors

The caughtErrors option is used for catch block arguments validation.

It has two settings:

• none - do not check error objects. This is the default setting.
• all - all named arguments must be used.

caughtErrors: none

Not specifying this rule is equivalent of assigning it to none.

Examples of correct code for the { "caughtErrors": "none" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "none" }]*/

try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrors: all

Examples of incorrect code for the { "caughtErrors": "all" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "all" }]*/

// 1 error
// "err" is defined but never used
try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrorsIgnorePattern

The caughtErrorsIgnorePattern option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern. For example, variables whose names begin with a string 'ignore'.

Examples of correct code for the { "caughtErrorsIgnorePattern": "^ignore" } option:

/*eslint no-unused-vars: ["error", { "caughtErrorsIgnorePattern": "^ignore" }]*/

try {
    //...
} catch (ignoreErr) {
    console.error("errors");
}

When Not To Use It

If you don't want to be notified about unused variables or function arguments, you can safely turn this rule off. Source: http://eslint.org/docs/rules/

          handle_l = $.data($handle[0], 'handle_l'),

Close

Disallow Unused Variables (no-unused-vars)

Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.

Rule Details

This rule is aimed at eliminating unused variables, functions, and parameters of functions.

A variable is considered to be used if any of the following are true:

• It represents a function that is called (doSomething())
• It is read (var y = x)
• It is passed into a function as an argument (doSomething(x))
• It is read inside of a function that is passed to another function (doSomething(function() { foo(); }))

A variable is not considered to be used if it is only ever assigned to (var x = 5) or declared.

Examples of incorrect code for this rule:

/*eslint no-unused-vars: "error"*/
/*global some_unused_var*/

// It checks variables you have defined as global
some_unused_var = 42;

var x;

// Write-only variables are not considered as used.
var y = 10;
y = 5;

// A read for a modification of itself is not considered as used.
var z = 0;
z = z + 1;

// By default, unused arguments cause warnings.
(function(foo) {
    return 5;
})();

// Unused recursive functions also cause warnings.
function fact(n) {
    if (n < 2) return 1;
    return n * fact(n - 1);
}

// When a function definition destructures an array, unused entries from the array also cause warnings.
function getY([x, y]) {
    return y;
}

Examples of correct code for this rule:

/*eslint no-unused-vars: "error"*/

var x = 10;
alert(x);

// foo is considered used here
myFunc(function foo() {
    // ...
}.bind(this));

(function(foo) {
    return foo;
})();

var myFunc;
myFunc = setTimeout(function() {
    // myFunc is considered used
    myFunc();
}, 50);

// Only the second argument from the descructured array is used.
function getY([, y]) {
    return y;
}

exported

In environments outside of CommonJS or ECMAScript modules, you may use var to create a global variable that may be used by other scripts. You can use the /* exported variableName */ comment block to indicate that this variable is being exported and therefore should not be considered unused.

Note that /* exported */ has no effect for any of the following:

• when the environment is node or commonjs
• when parserOptions.sourceType is module
• when ecmaFeatures.globalReturn is true

The line comment // exported variableName will not work as exported is not line-specific.

Examples of correct code for /* exported variableName */ operation:

/* exported global_var */

var global_var = 42;

Options

This rule takes one argument which can be a string or an object. The string settings are the same as those of the vars property (explained below).

By default this rule is enabled with all option for variables and after-used for arguments.

{
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "after-used", "ignoreRestSiblings": false }]
    }
}

vars

The vars option has two settings:

• all checks all variables for usage, including those in the global scope. This is the default setting.
• local checks only that locally-declared variables are used but will allow global variables to be unused.

vars: local

Examples of correct code for the { "vars": "local" } option:

/*eslint no-unused-vars: ["error", { "vars": "local" }]*/
/*global some_unused_var */

some_unused_var = 42;

varsIgnorePattern

The varsIgnorePattern option specifies exceptions not to check for usage: variables whose names match a regexp pattern. For example, variables whose names contain ignored or Ignored.

Examples of correct code for the { "varsIgnorePattern": "[iI]gnored" } option:

/*eslint no-unused-vars: ["error", { "varsIgnorePattern": "[iI]gnored" }]*/

var firstVarIgnored = 1;
var secondVar = 2;
console.log(secondVar);

args

The args option has three settings:

• after-used - only the last argument must be used. This allows you, for instance, to have two named parameters to a function and as long as you use the second argument, ESLint will not warn you about the first. This is the default setting.
• all - all named arguments must be used.
• none - do not check arguments.

args: after-used

Examples of incorrect code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", { "args": "after-used" }]*/

// 1 error
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

Examples of correct code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", {"args": "after-used"}]*/

(function(foo, bar, baz) {
    return baz;
})();

args: all

Examples of incorrect code for the { "args": "all" } option:

/*eslint no-unused-vars: ["error", { "args": "all" }]*/

// 2 errors
// "foo" is defined but never used
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

args: none

Examples of correct code for the { "args": "none" } option:

/*eslint no-unused-vars: ["error", { "args": "none" }]*/

(function(foo, bar, baz) {
    return bar;
})();

ignoreRestSiblings

The ignoreRestSiblings option is a boolean (default: false). Using a Rest Property it is possible to "omit" properties from an object, but by default the sibling properties are marked as "unused". With this option enabled the rest property's siblings are ignored.

Examples of correct code for the { "ignoreRestSiblings": true } option:

/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
// 'type' is ignored because it has a rest property sibling.
var { type, ...coords } = data;

argsIgnorePattern

The argsIgnorePattern option specifies exceptions not to check for usage: arguments whose names match a regexp pattern. For example, variables whose names begin with an underscore.

Examples of correct code for the { "argsIgnorePattern": "^_" } option:

/*eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }]*/

function foo(x, _y) {
    return x + 1;
}
foo();

caughtErrors

The caughtErrors option is used for catch block arguments validation.

It has two settings:

• none - do not check error objects. This is the default setting.
• all - all named arguments must be used.

caughtErrors: none

Not specifying this rule is equivalent of assigning it to none.

Examples of correct code for the { "caughtErrors": "none" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "none" }]*/

try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrors: all

Examples of incorrect code for the { "caughtErrors": "all" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "all" }]*/

// 1 error
// "err" is defined but never used
try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrorsIgnorePattern

The caughtErrorsIgnorePattern option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern. For example, variables whose names begin with a string 'ignore'.

Examples of correct code for the { "caughtErrorsIgnorePattern": "^ignore" } option:

/*eslint no-unused-vars: ["error", { "caughtErrorsIgnorePattern": "^ignore" }]*/

try {
    //...
} catch (ignoreErr) {
    console.error("errors");
}

When Not To Use It

If you don't want to be notified about unused variables or function arguments, you can safely turn this rule off. Source: http://eslint.org/docs/rules/

;(function ($, window, document, undefined) {

Close

Disallow Unused Variables (no-unused-vars)

Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.

Rule Details

This rule is aimed at eliminating unused variables, functions, and parameters of functions.

A variable is considered to be used if any of the following are true:

• It represents a function that is called (doSomething())
• It is read (var y = x)
• It is passed into a function as an argument (doSomething(x))
• It is read inside of a function that is passed to another function (doSomething(function() { foo(); }))

A variable is not considered to be used if it is only ever assigned to (var x = 5) or declared.

Examples of incorrect code for this rule:

/*eslint no-unused-vars: "error"*/
/*global some_unused_var*/

// It checks variables you have defined as global
some_unused_var = 42;

var x;

// Write-only variables are not considered as used.
var y = 10;
y = 5;

// A read for a modification of itself is not considered as used.
var z = 0;
z = z + 1;

// By default, unused arguments cause warnings.
(function(foo) {
    return 5;
})();

// Unused recursive functions also cause warnings.
function fact(n) {
    if (n < 2) return 1;
    return n * fact(n - 1);
}

// When a function definition destructures an array, unused entries from the array also cause warnings.
function getY([x, y]) {
    return y;
}

Examples of correct code for this rule:

/*eslint no-unused-vars: "error"*/

var x = 10;
alert(x);

// foo is considered used here
myFunc(function foo() {
    // ...
}.bind(this));

(function(foo) {
    return foo;
})();

var myFunc;
myFunc = setTimeout(function() {
    // myFunc is considered used
    myFunc();
}, 50);

// Only the second argument from the descructured array is used.
function getY([, y]) {
    return y;
}

exported

In environments outside of CommonJS or ECMAScript modules, you may use var to create a global variable that may be used by other scripts. You can use the /* exported variableName */ comment block to indicate that this variable is being exported and therefore should not be considered unused.

Note that /* exported */ has no effect for any of the following:

• when the environment is node or commonjs
• when parserOptions.sourceType is module
• when ecmaFeatures.globalReturn is true

The line comment // exported variableName will not work as exported is not line-specific.

Examples of correct code for /* exported variableName */ operation:

/* exported global_var */

var global_var = 42;

Options

This rule takes one argument which can be a string or an object. The string settings are the same as those of the vars property (explained below).

By default this rule is enabled with all option for variables and after-used for arguments.

{
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "after-used", "ignoreRestSiblings": false }]
    }
}

vars

The vars option has two settings:

• all checks all variables for usage, including those in the global scope. This is the default setting.
• local checks only that locally-declared variables are used but will allow global variables to be unused.

vars: local

Examples of correct code for the { "vars": "local" } option:

/*eslint no-unused-vars: ["error", { "vars": "local" }]*/
/*global some_unused_var */

some_unused_var = 42;

varsIgnorePattern

The varsIgnorePattern option specifies exceptions not to check for usage: variables whose names match a regexp pattern. For example, variables whose names contain ignored or Ignored.

Examples of correct code for the { "varsIgnorePattern": "[iI]gnored" } option:

/*eslint no-unused-vars: ["error", { "varsIgnorePattern": "[iI]gnored" }]*/

var firstVarIgnored = 1;
var secondVar = 2;
console.log(secondVar);

args

The args option has three settings:

• after-used - only the last argument must be used. This allows you, for instance, to have two named parameters to a function and as long as you use the second argument, ESLint will not warn you about the first. This is the default setting.
• all - all named arguments must be used.
• none - do not check arguments.

args: after-used

Examples of incorrect code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", { "args": "after-used" }]*/

// 1 error
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

Examples of correct code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", {"args": "after-used"}]*/

(function(foo, bar, baz) {
    return baz;
})();

args: all

Examples of incorrect code for the { "args": "all" } option:

/*eslint no-unused-vars: ["error", { "args": "all" }]*/

// 2 errors
// "foo" is defined but never used
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

args: none

Examples of correct code for the { "args": "none" } option:

/*eslint no-unused-vars: ["error", { "args": "none" }]*/

(function(foo, bar, baz) {
    return bar;
})();

ignoreRestSiblings

The ignoreRestSiblings option is a boolean (default: false). Using a Rest Property it is possible to "omit" properties from an object, but by default the sibling properties are marked as "unused". With this option enabled the rest property's siblings are ignored.

Examples of correct code for the { "ignoreRestSiblings": true } option:

/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
// 'type' is ignored because it has a rest property sibling.
var { type, ...coords } = data;

argsIgnorePattern

The argsIgnorePattern option specifies exceptions not to check for usage: arguments whose names match a regexp pattern. For example, variables whose names begin with an underscore.

Examples of correct code for the { "argsIgnorePattern": "^_" } option:

/*eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }]*/

function foo(x, _y) {
    return x + 1;
}
foo();

caughtErrors

The caughtErrors option is used for catch block arguments validation.

It has two settings:

• none - do not check error objects. This is the default setting.
• all - all named arguments must be used.

caughtErrors: none

Not specifying this rule is equivalent of assigning it to none.

Examples of correct code for the { "caughtErrors": "none" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "none" }]*/

try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrors: all

Examples of incorrect code for the { "caughtErrors": "all" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "all" }]*/

// 1 error
// "err" is defined but never used
try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrorsIgnorePattern

The caughtErrorsIgnorePattern option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern. For example, variables whose names begin with a string 'ignore'.

Examples of correct code for the { "caughtErrorsIgnorePattern": "^ignore" } option:

/*eslint no-unused-vars: ["error", { "caughtErrorsIgnorePattern": "^ignore" }]*/

try {
    //...
} catch (ignoreErr) {
    console.error("errors");
}

When Not To Use It

If you don't want to be notified about unused variables or function arguments, you can safely turn this rule off. Source: http://eslint.org/docs/rules/

          if (!!self.cache.active) {

Close

disallow unnecessary boolean casts (no-extra-boolean-cast)

In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) or a Boolean call is unnecessary. For example, these if statements are equivalent:

if (!!foo) {
    // ...
}

if (Boolean(foo)) {
    // ...
}

if (foo) {
    // ...
}

Rule Details

This rule disallows unnecessary boolean casts.

Examples of incorrect code for this rule:

/*eslint no-extra-boolean-cast: "error"*/

var foo = !!!bar;

var foo = !!bar ? baz : bat;

var foo = Boolean(!!bar);

var foo = new Boolean(!!bar);

if (!!foo) {
    // ...
}

if (Boolean(foo)) {
    // ...
}

while (!!foo) {
    // ...
}

do {
    // ...
} while (Boolean(foo));

for (; !!foo; ) {
    // ...
}

Examples of correct code for this rule:

/*eslint no-extra-boolean-cast: "error"*/

var foo = !!bar;
var foo = Boolean(bar);

function foo() {
    return !!bar;
}

var foo = bar ? !!baz : !!bat;

Source: http://eslint.org/docs/rules/

          handle_o = $.data($handle[0], 'handle_o'),

Close

Disallow Unused Variables (no-unused-vars)

Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.

Rule Details

This rule is aimed at eliminating unused variables, functions, and parameters of functions.

A variable is considered to be used if any of the following are true:

• It represents a function that is called (doSomething())
• It is read (var y = x)
• It is passed into a function as an argument (doSomething(x))
• It is read inside of a function that is passed to another function (doSomething(function() { foo(); }))

A variable is not considered to be used if it is only ever assigned to (var x = 5) or declared.

Examples of incorrect code for this rule:

/*eslint no-unused-vars: "error"*/
/*global some_unused_var*/

// It checks variables you have defined as global
some_unused_var = 42;

var x;

// Write-only variables are not considered as used.
var y = 10;
y = 5;

// A read for a modification of itself is not considered as used.
var z = 0;
z = z + 1;

// By default, unused arguments cause warnings.
(function(foo) {
    return 5;
})();

// Unused recursive functions also cause warnings.
function fact(n) {
    if (n < 2) return 1;
    return n * fact(n - 1);
}

// When a function definition destructures an array, unused entries from the array also cause warnings.
function getY([x, y]) {
    return y;
}

Examples of correct code for this rule:

/*eslint no-unused-vars: "error"*/

var x = 10;
alert(x);

// foo is considered used here
myFunc(function foo() {
    // ...
}.bind(this));

(function(foo) {
    return foo;
})();

var myFunc;
myFunc = setTimeout(function() {
    // myFunc is considered used
    myFunc();
}, 50);

// Only the second argument from the descructured array is used.
function getY([, y]) {
    return y;
}

exported

In environments outside of CommonJS or ECMAScript modules, you may use var to create a global variable that may be used by other scripts. You can use the /* exported variableName */ comment block to indicate that this variable is being exported and therefore should not be considered unused.

Note that /* exported */ has no effect for any of the following:

• when the environment is node or commonjs
• when parserOptions.sourceType is module
• when ecmaFeatures.globalReturn is true

The line comment // exported variableName will not work as exported is not line-specific.

Examples of correct code for /* exported variableName */ operation:

/* exported global_var */

var global_var = 42;

Options

This rule takes one argument which can be a string or an object. The string settings are the same as those of the vars property (explained below).

By default this rule is enabled with all option for variables and after-used for arguments.

{
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "after-used", "ignoreRestSiblings": false }]
    }
}

vars

The vars option has two settings:

• all checks all variables for usage, including those in the global scope. This is the default setting.
• local checks only that locally-declared variables are used but will allow global variables to be unused.

vars: local

Examples of correct code for the { "vars": "local" } option:

/*eslint no-unused-vars: ["error", { "vars": "local" }]*/
/*global some_unused_var */

some_unused_var = 42;

varsIgnorePattern

The varsIgnorePattern option specifies exceptions not to check for usage: variables whose names match a regexp pattern. For example, variables whose names contain ignored or Ignored.

Examples of correct code for the { "varsIgnorePattern": "[iI]gnored" } option:

/*eslint no-unused-vars: ["error", { "varsIgnorePattern": "[iI]gnored" }]*/

var firstVarIgnored = 1;
var secondVar = 2;
console.log(secondVar);

args

The args option has three settings:

• after-used - only the last argument must be used. This allows you, for instance, to have two named parameters to a function and as long as you use the second argument, ESLint will not warn you about the first. This is the default setting.
• all - all named arguments must be used.
• none - do not check arguments.

args: after-used

Examples of incorrect code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", { "args": "after-used" }]*/

// 1 error
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

Examples of correct code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", {"args": "after-used"}]*/

(function(foo, bar, baz) {
    return baz;
})();

args: all

Examples of incorrect code for the { "args": "all" } option:

/*eslint no-unused-vars: ["error", { "args": "all" }]*/

// 2 errors
// "foo" is defined but never used
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

args: none

Examples of correct code for the { "args": "none" } option:

/*eslint no-unused-vars: ["error", { "args": "none" }]*/

(function(foo, bar, baz) {
    return bar;
})();

ignoreRestSiblings

The ignoreRestSiblings option is a boolean (default: false). Using a Rest Property it is possible to "omit" properties from an object, but by default the sibling properties are marked as "unused". With this option enabled the rest property's siblings are ignored.

Examples of correct code for the { "ignoreRestSiblings": true } option:

/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
// 'type' is ignored because it has a rest property sibling.
var { type, ...coords } = data;

argsIgnorePattern

The argsIgnorePattern option specifies exceptions not to check for usage: arguments whose names match a regexp pattern. For example, variables whose names begin with an underscore.

Examples of correct code for the { "argsIgnorePattern": "^_" } option:

/*eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }]*/

function foo(x, _y) {
    return x + 1;
}
foo();

caughtErrors

The caughtErrors option is used for catch block arguments validation.

It has two settings:

• none - do not check error objects. This is the default setting.
• all - all named arguments must be used.

caughtErrors: none

Not specifying this rule is equivalent of assigning it to none.

Examples of correct code for the { "caughtErrors": "none" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "none" }]*/

try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrors: all

Examples of incorrect code for the { "caughtErrors": "all" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "all" }]*/

// 1 error
// "err" is defined but never used
try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrorsIgnorePattern

The caughtErrorsIgnorePattern option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern. For example, variables whose names begin with a string 'ignore'.

Examples of correct code for the { "caughtErrorsIgnorePattern": "^ignore" } option:

/*eslint no-unused-vars: ["error", { "caughtErrorsIgnorePattern": "^ignore" }]*/

try {
    //...
} catch (ignoreErr) {
    console.error("errors");
}

When Not To Use It

If you don't want to be notified about unused variables or function arguments, you can safely turn this rule off. Source: http://eslint.org/docs/rules/

      Foundation.inherit(this, 'throttle');

Close

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. Source: http://eslint.org/docs/rules/

      if (!!$(this.scope).attr(self.attr_name())) {

Close

disallow unnecessary boolean casts (no-extra-boolean-cast)

In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) or a Boolean call is unnecessary. For example, these if statements are equivalent:

if (!!foo) {
    // ...
}

if (Boolean(foo)) {
    // ...
}

if (foo) {
    // ...
}

Rule Details

This rule disallows unnecessary boolean casts.

Examples of incorrect code for this rule:

/*eslint no-extra-boolean-cast: "error"*/

var foo = !!!bar;

var foo = !!bar ? baz : bat;

var foo = Boolean(!!bar);

var foo = new Boolean(!!bar);

if (!!foo) {
    // ...
}

if (Boolean(foo)) {
    // ...
}

while (!!foo) {
    // ...
}

do {
    // ...
} while (Boolean(foo));

for (; !!foo; ) {
    // ...
}

Examples of correct code for this rule:

/*eslint no-extra-boolean-cast: "error"*/

var foo = !!bar;
var foo = Boolean(bar);

function foo() {
    return !!bar;
}

var foo = bar ? !!baz : !!bat;

Source: http://eslint.org/docs/rules/

        if (Foundation.rtl && !settings.vertical) {

Close

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. Source: http://eslint.org/docs/rules/

  Foundation.libs.slider = {

Close

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. Source: http://eslint.org/docs/rules/

        .on('change.fndtn.slider', function (e) {

Close

Disallow Unused Variables (no-unused-vars)

Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.

Rule Details

This rule is aimed at eliminating unused variables, functions, and parameters of functions.

A variable is considered to be used if any of the following are true:

• It represents a function that is called (doSomething())
• It is read (var y = x)
• It is passed into a function as an argument (doSomething(x))
• It is read inside of a function that is passed to another function (doSomething(function() { foo(); }))

A variable is not considered to be used if it is only ever assigned to (var x = 5) or declared.

Examples of incorrect code for this rule:

/*eslint no-unused-vars: "error"*/
/*global some_unused_var*/

// It checks variables you have defined as global
some_unused_var = 42;

var x;

// Write-only variables are not considered as used.
var y = 10;
y = 5;

// A read for a modification of itself is not considered as used.
var z = 0;
z = z + 1;

// By default, unused arguments cause warnings.
(function(foo) {
    return 5;
})();

// Unused recursive functions also cause warnings.
function fact(n) {
    if (n < 2) return 1;
    return n * fact(n - 1);
}

// When a function definition destructures an array, unused entries from the array also cause warnings.
function getY([x, y]) {
    return y;
}

Examples of correct code for this rule:

/*eslint no-unused-vars: "error"*/

var x = 10;
alert(x);

// foo is considered used here
myFunc(function foo() {
    // ...
}.bind(this));

(function(foo) {
    return foo;
})();

var myFunc;
myFunc = setTimeout(function() {
    // myFunc is considered used
    myFunc();
}, 50);

// Only the second argument from the descructured array is used.
function getY([, y]) {
    return y;
}

exported

In environments outside of CommonJS or ECMAScript modules, you may use var to create a global variable that may be used by other scripts. You can use the /* exported variableName */ comment block to indicate that this variable is being exported and therefore should not be considered unused.

Note that /* exported */ has no effect for any of the following:

• when the environment is node or commonjs
• when parserOptions.sourceType is module
• when ecmaFeatures.globalReturn is true

The line comment // exported variableName will not work as exported is not line-specific.

Examples of correct code for /* exported variableName */ operation:

/* exported global_var */

var global_var = 42;

Options

This rule takes one argument which can be a string or an object. The string settings are the same as those of the vars property (explained below).

By default this rule is enabled with all option for variables and after-used for arguments.

{
    "rules": {
        "no-unused-vars": ["error", { "vars": "all", "args": "after-used", "ignoreRestSiblings": false }]
    }
}

vars

The vars option has two settings:

• all checks all variables for usage, including those in the global scope. This is the default setting.
• local checks only that locally-declared variables are used but will allow global variables to be unused.

vars: local

Examples of correct code for the { "vars": "local" } option:

/*eslint no-unused-vars: ["error", { "vars": "local" }]*/
/*global some_unused_var */

some_unused_var = 42;

varsIgnorePattern

The varsIgnorePattern option specifies exceptions not to check for usage: variables whose names match a regexp pattern. For example, variables whose names contain ignored or Ignored.

Examples of correct code for the { "varsIgnorePattern": "[iI]gnored" } option:

/*eslint no-unused-vars: ["error", { "varsIgnorePattern": "[iI]gnored" }]*/

var firstVarIgnored = 1;
var secondVar = 2;
console.log(secondVar);

args

The args option has three settings:

• after-used - only the last argument must be used. This allows you, for instance, to have two named parameters to a function and as long as you use the second argument, ESLint will not warn you about the first. This is the default setting.
• all - all named arguments must be used.
• none - do not check arguments.

args: after-used

Examples of incorrect code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", { "args": "after-used" }]*/

// 1 error
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

Examples of correct code for the default { "args": "after-used" } option:

/*eslint no-unused-vars: ["error", {"args": "after-used"}]*/

(function(foo, bar, baz) {
    return baz;
})();

args: all

Examples of incorrect code for the { "args": "all" } option:

/*eslint no-unused-vars: ["error", { "args": "all" }]*/

// 2 errors
// "foo" is defined but never used
// "baz" is defined but never used
(function(foo, bar, baz) {
    return bar;
})();

args: none

Examples of correct code for the { "args": "none" } option:

/*eslint no-unused-vars: ["error", { "args": "none" }]*/

(function(foo, bar, baz) {
    return bar;
})();

ignoreRestSiblings

The ignoreRestSiblings option is a boolean (default: false). Using a Rest Property it is possible to "omit" properties from an object, but by default the sibling properties are marked as "unused". With this option enabled the rest property's siblings are ignored.

Examples of correct code for the { "ignoreRestSiblings": true } option:

/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
// 'type' is ignored because it has a rest property sibling.
var { type, ...coords } = data;

argsIgnorePattern

The argsIgnorePattern option specifies exceptions not to check for usage: arguments whose names match a regexp pattern. For example, variables whose names begin with an underscore.

Examples of correct code for the { "argsIgnorePattern": "^_" } option:

/*eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }]*/

function foo(x, _y) {
    return x + 1;
}
foo();

caughtErrors

The caughtErrors option is used for catch block arguments validation.

It has two settings:

• none - do not check error objects. This is the default setting.
• all - all named arguments must be used.

caughtErrors: none

Not specifying this rule is equivalent of assigning it to none.

Examples of correct code for the { "caughtErrors": "none" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "none" }]*/

try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrors: all

Examples of incorrect code for the { "caughtErrors": "all" } option:

/*eslint no-unused-vars: ["error", { "caughtErrors": "all" }]*/

// 1 error
// "err" is defined but never used
try {
    //...
} catch (err) {
    console.error("errors");
}

caughtErrorsIgnorePattern

The caughtErrorsIgnorePattern option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern. For example, variables whose names begin with a string 'ignore'.

Examples of correct code for the { "caughtErrorsIgnorePattern": "^ignore" } option:

/*eslint no-unused-vars: ["error", { "caughtErrorsIgnorePattern": "^ignore" }]*/

try {
    //...
} catch (ignoreErr) {
    console.error("errors");
}

When Not To Use It

If you don't want to be notified about unused variables or function arguments, you can safely turn this rule off. Source: http://eslint.org/docs/rules/

;(function ($, window, document, undefined) {

Close

disallow unnecessary semicolons (no-extra-semi)

Typing mistakes and misunderstandings about where semicolons are required can lead to semicolons that are unnecessary. While not technically an error, extra semicolons can cause confusion when reading code.

Rule Details

This rule disallows unnecessary semicolons.

Examples of incorrect code for this rule:

/*eslint no-extra-semi: "error"*/

var x = 5;;

function foo() {
    // code
};

Examples of correct code for this rule:

/*eslint no-extra-semi: "error"*/

var x = 5;

var foo = function() {
    // code
};

When Not To Use It

If you intentionally use extra semicolons then you can disable this rule.

Related Rules

• [semi](semi.md)
• [semi-spacing](semi-spacing.md) Source: http://eslint.org/docs/rules/

      if (Foundation.rtl && !settings.vertical) {

Close

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. Source: http://eslint.org/docs/rules/

              if ($.data(self.cache.active[0], 'settings').vertical) {
                var scroll_offset = 0;
                if (!e.pageY) {
                  scroll_offset = window.scrollY;
                }

Close

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 129.

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

            if ($.data(self.cache.active[0], 'settings').vertical) {
              var scroll_offset = 0;
              if (!e.pageY) {
                scroll_offset = window.scrollY;
              }

Close

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 129.

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

      if (settings.vertical) {
        $.data(handle, 'bar_o', $(handle).parent().offset().top);
        $.data(handle, 'bar_l', $(handle).parent().outerHeight());
        $.data(handle, 'handle_o', $(handle).offset().top);
        $.data(handle, 'handle_l', $(handle).outerHeight());

Close

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 121.

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

      } else {
        $.data(handle, 'bar_o', $(handle).parent().offset().left);
        $.data(handle, 'bar_l', $(handle).parent().outerWidth());
        $.data(handle, 'handle_o', $(handle).offset().left);
        $.data(handle, 'handle_l', $(handle).outerWidth());

Close

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 121.

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

      if (vertical) {
        $(ele)
          .css('-webkit-transform', 'translateY(' + offset + 'px)')
          .css('-moz-transform', 'translateY(' + offset + 'px)')
          .css('-ms-transform', 'translateY(' + offset + 'px)')

Close

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

      } else {
        $(ele)
          .css('-webkit-transform', 'translateX(' + offset + 'px)')
          .css('-moz-transform', 'translateX(' + offset + 'px)')
          .css('-ms-transform', 'translateX(' + offset + 'px)')

Close

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

    init : function (scope, method, options) {
      Foundation.inherit(this, 'throttle');
      this.bindings(method, options);
      this.reflow();
    },

Close

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 47.

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