* @param {String} [options.cidr] a ip range in which the rule is applied to e.g. '0.0.0.0/0' for all

Close

enforce a maximum line length (max-len)

Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).

var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long

Rule Details

This rule enforces a maximum line length to increase code readability and maintainability. The length of a line is defined as the number of Unicode characters in the line.

Options

This rule has a number or object option:

• "code" (default 80) enforces a maximum line length
• "tabWidth" (default 4) specifies the character width for tab characters
• "comments" enforces a maximum line length for comments; defaults to value of code
• "ignorePattern" ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON
• "ignoreComments": true ignores all trailing comments and comments on their own line
• "ignoreTrailingComments": true ignores only trailing comments
• "ignoreUrls": true ignores lines that contain a URL
• "ignoreStrings": true ignores lines that contain a double-quoted or single-quoted string
• "ignoreTemplateLiterals": true ignores lines that contain a template literal
• "ignoreRegExpLiterals": true ignores lines that contain a RegExp literal

code

Examples of incorrect code for this rule with the default { "code": 80 } option:

/*eslint max-len: ["error", 80]*/

var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };

Examples of correct code for this rule with the default { "code": 80 } option:

/*eslint max-len: ["error", 80]*/

var foo = {
  "bar": "This is a bar.",
  "baz": { "qux": "This is a qux" },
  "easier": "to read"
};

tabWidth

Examples of incorrect code for this rule with the default { "tabWidth": 4 } option:

/*eslint max-len: ["error", 80, 4]*/

\t  \t  var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };

Examples of correct code for this rule with the default { "tabWidth": 4 } option:

/*eslint max-len: ["error", 80, 4]*/

\t  \t  var foo = {
\t  \t  \t  \t  "bar": "This is a bar.",
\t  \t  \t  \t  "baz": { "qux": "This is a qux" }
\t  \t  };

comments

Examples of incorrect code for this rule with the { "comments": 65 } option:

/*eslint max-len: ["error", { "comments": 65 }]*/

/**
 * This is a comment that violates the maximum line length we have specified
**/

ignoreComments

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

/*eslint max-len: ["error", { "ignoreComments": true }]*/

/**
 * This is a really really really really really really really really really long comment
**/

ignoreTrailingComments

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

/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/

var foo = 'bar'; // This is a really really really really really really really long comment

ignoreUrls

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

/*eslint max-len: ["error", { "ignoreUrls": true }]*/

var url = 'https://www.example.com/really/really/really/really/really/really/really/long';

ignoreStrings

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

/*eslint max-len: ["error", { "ignoreStrings": true }]*/

var longString = 'this is a really really really really really long string!';

ignoreTemplateLiterals

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

/*eslint max-len: ["error", { "ignoreTemplateLiterals": true }]*/

var longTemplateLiteral = `this is a really really really really really long template literal!`;

ignoreRegExpLiterals

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

/*eslint max-len: ["error", { "ignoreRegExpLiterals": true }]*/

var longRegExpLiteral = /this is a really really really really really long regular expression!/;

ignorePattern

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

/*eslint max-len: ["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(/" }]*/

var dep = require('really/really/really/really/really/really/really/really/long/module');

Related Rules

• [complexity](complexity.md)
• [max-depth](max-depth.md)
• [max-nested-callbacks](max-nested-callbacks.md)
• [max-params](max-params.md)
• [max-statements](max-statements.md) Source: http://eslint.org/docs/rules/

    createFirewallRule(id, start_port, options) {

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/