netflix / eslint-config-netflix

Shared ESLint config for Netflix JavaScript

eslint-config-netflix

See ESLint docs on flat configuration

npm install --save-dev @netflix/eslint-config
npm test

Philosophy:

• Share rules that identify syntax associated with common software bugs (e.g. no-fallthrough)
• Adopt rules that steer developers away from outdated language features (e.g. no-var)
• Avoid the temptation to enforce stylistic preferences; integrators should do this locally
• Be more useful than js.configs.recommended.rules

---

Example usage:

import globals from 'globals';
import NetflixCommon from '@netflix/eslint-config';

export default [
  {
    files: ['**/*.js'],
    languageOptions: { globals: globals.browser },
    ...NetflixCommon,
  },
  {
    ignores: ['node_modules'],
  },
];

eslint-config-netflix's Issues

Publish latest to @Netflix/eslint-config-netflix

Title says it all — #11 describes install steps that currently do not work:

npm install --save-dev @Netflix/eslint-config-netflix

Older versions can still be installed via:

npm install --save-dev eslint-config-netflix

Audit 2.0 rules for deprecation or inclusion in 3.0

2.0 formatting rules removed in 3.0 (deprecated by ESLint)

• array-bracket-spacing
• comma-style
• eol-last
• generator-star-spacing
• indent
• jsx-quotes
• key-spacing
• no-extra-parens
• no-multi-spaces
• no-multiple-empty-lines
• object-curly-spacing
• quote-props
• semi-spacing
• space-before-blocks
• space-before-function-paren
• template-curly-spacing
• yield-star-spacing

2.0 rules now covered by eslint:recommended in 3.0

• no-const-assign
• no-debugger
• no-empty-pattern
• no-fallthrough (removed warning override, now error per eslint:recommended)
• no-func-assign
• no-irregular-whitespace
• no-prototype-builtins (removed warning override, now error per eslint:recommended)
• no-redeclare
• no-self-assign
• no-with
• valid-typeof

2.0 rules carried forward to 3.0

• array-callback-return
• comma-dangle (deprecated, will remove in 4.0)
• curly (deprecated, will remove in 4.0)
• dot-notation
• eqeqeq
• guard-for-in
• no-bitwise
• no-caller
• no-eval
• no-extend-native
• no-loop-func
• no-proto
• no-script-url
• no-sequences
• no-shadow
• no-undef
• no-unused-expressions
• no-unused-vars
• no-var
• prefer-arrow-callback
• prefer-const
• quotes (deprecated, will remove in 4.0)
• semi (deprecated, will remove in 4.0)

2.0 rules removed in 3.0 (rationale below)

• camelcase
• class-methods-use-this
• new-cap
• no-empty
• no-empty-function
• no-iterator
• no-lone-blocks
• no-multi-str
• no-new
• no-plusplus
• no-template-curly-in-string
• no-underscore-dangle
• no-useless-constructor
• no-useless-rename
• prefer-rest-params
• prefer-spread
• prefer-template
• strict

3.0 rules added

• js.configs.recommended.rules
• no-console
• no-constant-binary-expression
• no-undef-init
• prefer-object-has-own

Consider no-require-imports inclusion

Perhaps consider https://typescript-eslint.io/rules/no-require-imports/

Pro: require() is a non-standard holding back the web
Con: this rule would aggressively warn about something that can't be changed in most developer scenarios

Rename primary branch to main

Title says it all — do this after #11 is merged

Don't manually update package-lock.json when publishing

The package-lock.json file should always be derived from npm install - if we manually edit it there is no guarantee that our edits will persist through the next install.

Migrate to ESLint 9.0

This should likely be considered a breaking change, as the eslint:recommended rules have some adjustments:

https://eslint.org/docs/latest/use/migrate-to-9.0.0#eslint-recommended

array-callback-return warnings

See: https://eslint.org/docs/latest/rules/array-callback-return

With the rule enabled, this causes a warning:

const index = list.findLastIndex(candidateId => {
  const candidate = input[candidateId];
  if (candidate.ok === true) {
    return true;
  }
});

Developers must instead rewrite like this:

const index = list.findLastIndex(candidateId => {
  const candidate = input[candidateId];
  if (candidate.ok === true) {
    return true;
  }
  return undefined;
});

Musings: Warning developers to add return undefined; to conclude some function calls and not others is inconsistent. Requiring developers to add return undefined; at all seems superfluous.

In #19 we said:

using these methods carry certain semantics. If you don’t want to actually create an object, different methods exist with the appropriate semantics.

Is the rule doing what we expect?

comma-dangle, quotes, semi rules moved to @stylistic/eslint-plugin-js

See https://eslint.org/blog/2023/10/deprecating-formatting-rules/

Detailed deprecation rationale: eslint/eslint#17522

All of these rules will be deprecated as of the next release, but will not be removed until at least ESLint v10.0.0 (if not later).

Example message for comma-dangle

This rule was deprecated in ESLint v8.53.0. Please use the corresponding rule in @stylistic/eslint-plugin-js.