Possible Errors

for-direction

Enforce “for” loop update clause moving the counter in the right direction

getter-return

Enforce return statements in getters

no-await-in-loop

Disallow await inside of loops

no-async-promise-executor

Disallow using an async function as a Promise executor

no-compare-neg-zero

Disallow comparing against -0

no-cond-assign

Disallow assignment operators in conditional expressions

no-control-regex

Disallow control characters in regular expressions

no-constant-condition

Disallow constant expressions in conditions

no-console

Disallow the use of console

no-debugger

Disallow the use of debugger

no-dupe-args

Disallow duplicate arguments in function definitions

no-dupe-keys

Disallow duplicate keys in object literals

no-duplicate-case

Disallow duplicate case labels

no-empty

Disallow empty block statements

no-empty-character-class

Disallow empty character classes in regular expressions

no-ex-assign

Disallow reassigning exceptions in catch clauses

no-extra-boolean-cast

Disallow unnecessary boolean casts

no-extra-parens

Disallow unnecessary parentheses

no-extra-semi

Disallow unnecessary semicolons

no-func-assign

Disallow reassigning function declarations

no-inner-declarations

Disallow variable or function declarations in nested blocks

no-invalid-regexp

Disallow invalid regular expression strings in RegExp constructors

no-irregular-whitespace

Disallow irregular whitespace outside of strings and comments

no-misleading-character-class

Disallow characters which are made with multiple code points in character class syntax

no-obj-calls

Disallow calling global object properties as functions

no-prototype-builtins

Disallow calling some Object.prototype methods directly on objects

no-regex-spaces

Disallow multiple spaces in regular expressions

no-sparse-arrays

Disallow sparse arrays

no-template-curly-in-string

Disallow template literal placeholder syntax in regular strings

no-unexpected-multiline

Disallow confusing multiline expressions

no-unreachable

Disallow unreachable code after return, throw, continue, and break statements

no-unsafe-finally

Disallow control flow statements in finally blocks

no-unsafe-negation

Disallow negating the left operand of relational operators

require-atomic-updates

Disallow assignments that can lead to race conditions due to usage of await or yield

use-isnan

Require calls to isNaN() when checking for NaN

valid-jsdoc

Enforce valid JSDoc comments

valid-typeof

Enforce comparing typeof expressions against valid strings

Best Practices

Strict Mode

Variables

Node.js and CommonJS

Stylistic Issues

ECMAScript 6

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no-duplicate-case

- Disallow duplicate case labels

This rule disallows duplicate test expressions in case clauses of switch statements.

What ESLint should do when it catches the rule break

Show a warning

Rule examples

You can check them out here.

no-dupe-keys no-empty