Possible Errors

Best Practices

Strict Mode

Variables

Node.js and CommonJS

Stylistic Issues

array-bracket-newline

Enforce linebreaks after opening and before closing array brackets

array-bracket-spacing

Enforce consistent spacing inside array brackets

array-element-newline

Enforce line breaks after each array element

block-spacing

Disallow or enforce spaces inside of blocks after opening block and before closing block

brace-style

Enforce consistent brace style for blocks

camelcase

Enforce camelcase naming convention

capitalized-comments

Enforce or disallow capitalization of the first letter of a comment

comma-dangle

Require or disallow trailing commas

comma-spacing

Enforce consistent spacing before and after commas

comma-style

Enforce consistent comma style

computed-property-spacing

Enforce consistent spacing inside computed property brackets

consistent-this

Enforce consistent naming when capturing the current execution context

eol-last

Require or disallow newline at the end of files

func-call-spacing

Require or disallow spacing between function identifiers and their invocations

func-name-matching

Require function names to match the name of the variable or property to which they are assigned

func-names

Require or disallow named function expressions

func-style

Enforce the consistent use of either function declarations or expressions

function-paren-newline

Enforce consistent line breaks inside function parentheses

id-blacklist

Disallow specified identifiers

id-length

Enforce minimum and maximum identifier lengths

id-match

Require identifiers to match a specified regular expression

implicit-arrow-linebreak

Enforce the location of arrow function bodies

indent

Enforce consistent indentation

jsx-quotes

Enforce the consistent use of either double or single quotes in JSX attributes

key-spacing

Enforce consistent spacing between keys and values in object literal properties

keyword-spacing

Enforce consistent spacing before and after keywords

line-comment-position

Enforce position of line comments

linebreak-style

Enforce consistent linebreak style

lines-around-comment

Require empty lines around comments

lines-between-class-members

Require or disallow an empty line between class members

max-depth

Enforce a maximum depth that blocks can be nested

max-len

Enforce a maximum line length

max-lines

Enforce a maximum number of lines per file

max-lines-per-function

Enforce a maximum number of line of code in a function

max-nested-callbacks

Enforce a maximum depth that callbacks can be nested

max-params

Enforce a maximum number of parameters in function definitions

max-statements

Enforce a maximum number of statements allowed in function blocks

max-statements-per-line

Enforce a maximum number of statements allowed per line

multiline-comment-style

Enforce a particular style for multiline comments

multiline-ternary

Enforce newlines between operands of ternary expressions

new-cap

Require constructor names to begin with a capital letter

new-parens

Require parentheses when invoking a constructor with no arguments

newline-per-chained-call

Require a newline after each call in a method chain

no-array-constructor

Disallow Array constructors

no-bitwise

Disallow bitwise operators

no-continue

Disallow continue statements

no-inline-comments

Disallow inline comments after code

no-lonely-if

Disallow if statements as the only statement in else blocks

no-mixed-operators

Disallow mixed binary operators

no-mixed-spaces-and-tabs

Disallow mixed spaces and tabs for indentation

no-multi-assign

Disallow use of chained assignment expressions

no-multiple-empty-lines

Disallow multiple empty lines

no-negated-condition

Disallow negated conditions

no-nested-ternary

Disallow nested ternary expressions

no-new-object

Disallow Object constructors

no-plusplus

Disallow the unary operators ++ and --

no-restricted-syntax

Disallow specified syntax

no-tabs

Disallow all tabs

no-ternary

Disallow ternary operators

no-trailing-spaces

Disallow trailing whitespace at the end of lines

no-underscore-dangle

Disallow dangling underscores in identifiers

no-unneeded-ternary

Disallow ternary operators when simpler alternatives exist

no-whitespace-before-property

Disallow whitespace before properties

nonblock-statement-body-position

Enforce the location of single-line statements

object-curly-newline

Enforce consistent line breaks inside braces

object-curly-spacing

Enforce consistent spacing inside braces

object-property-newline

Enforce placing object properties on separate lines

one-var

Enforce variables to be declared either together or separately in functions

one-var-declaration-per-line

Require or disallow newlines around variable declarations

operator-assignment

Require or disallow assignment operator shorthand where possible

operator-linebreak

Enforce consistent linebreak style for operators

padded-blocks

Require or disallow padding within blocks

padding-line-between-statements

Require or disallow padding lines between statements

prefer-object-spread

Disallow using Object.assign with an object literal as the first argument and prefer the use of object spread instead

quote-props

Require quotes around object literal property names

quotes

Enforce the consistent use of either backticks, double, or single quotes

require-jsdoc

Require JSDoc comments

semi

Require or disallow semicolons instead of ASI

semi-spacing

Enforce consistent spacing before and after semicolons

semi-style

Enforce location of semicolons

sort-keys

Require object keys to be sorted

sort-vars

Require variables within the same declaration block to be sorted

space-before-blocks

Enforce consistent spacing before blocks

space-before-function-paren

Enforce consistent spacing before function definition opening parenthesis

space-in-parens

Enforce consistent spacing inside parentheses

space-infix-ops

Require spacing around infix operators

space-unary-ops

Enforce consistent spacing before or after unary operators

spaced-comment

Enforce consistent spacing after the // or /* in a comment

switch-colon-spacing

Enforce spacing around colons of switch statements

template-tag-spacing

Require or disallow spacing between template tags and their literals

unicode-bom

Require or disallow Unicode byte order mark (BOM)

wrap-regex

Require parenthesis around regex literals

ECMAScript 6

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max-lines

- Enforce a maximum number of lines per file

This rule enforces a maximum number of lines per file, in order to aid in maintainability and reduce complexity.

What ESLint should do when it catches the rule break

Show a warning

Options

skipBlankLines

Ignores lines made up purely of whitespace.

skipComments

Ignores lines containing just comments.

max

Specifies a maximum number of lines in a file.

Rule examples

You can check them out here.

max-len max-lines-per-function