eslint-plugin-react

What is eslint-plugin-react?

The eslint-plugin-react is a plugin for ESLint that provides linting utilities for React and JSX specific code. It helps developers adhere to best practices and avoid common pitfalls in React development.

What are eslint-plugin-react's main functionalities?

JSX-specific rules

Enforces rules specific to JSX, such as ensuring that any variables used in JSX are defined and that React is in scope when using JSX.

"react/jsx-uses-react": "error", "react/jsx-uses-vars": "error"

Hooks rules

Provides rules that enforce the correct usage of React Hooks, such as ensuring that hooks are called in the same order on every render and that dependencies are specified correctly for useEffect.

"react-hooks/rules-of-hooks": "error", "react-hooks/exhaustive-deps": "warn"

Prop-types validation

Ensures that prop types are correctly defined and used within React components, helping to catch type-related bugs.

"react/prop-types": "error"

Component lifecycle

Warns about usage of deprecated methods in React component lifecycle, encouraging developers to update to newer APIs.

"react/no-deprecated": "warn"

Best practices

Encourages best practices by warning against common anti-patterns like using array indices as keys or mutating state directly.

"react/no-array-index-key": "warn", "react/no-direct-mutation-state": "error"

Other packages similar to eslint-plugin-react

eslint-plugin-vue

Similar to eslint-plugin-react, eslint-plugin-vue provides linting rules specific to Vue.js framework. It helps enforce Vue-specific best practices and coding standards.

eslint-plugin-angular

This plugin is similar to eslint-plugin-react but for Angular applications. It contains rules that enforce best practices and conventions in AngularJS projects.

eslint-plugin-jsx-a11y

While not specific to React, eslint-plugin-jsx-a11y works well with eslint-plugin-react to enforce accessibility practices in JSX elements.

eslint-plugin-preact

This plugin is designed for Preact (a fast 3kB alternative to React with the same ES6 API) and provides linting rules tailored to Preact codebases.

README

eslint-plugin-react

===================

React specific linting rules for eslint

Installation

npm install eslint eslint-plugin-react --save-dev

It is also possible to install ESLint globally rather than locally (using npm install -g eslint). However, this is not recommended, and any plugins or shareable configs that you use must be installed locally in either case.

Configuration (legacy: .eslintrc*)

Use our preset to get reasonable defaults:

  "extends": [
    "eslint:recommended",
    "plugin:react/recommended"
  ]

If you are using the new JSX transform from React 17, extend react/jsx-runtime in your eslint config (add "plugin:react/jsx-runtime" to "extends") to disable the relevant rules.

You should also specify settings that will be shared across all the plugin rules. (More about eslint shared settings)

{
  "settings": {
    "react": {
      "createClass": "createReactClass", // Regex for Component Factory to use,
                                         // default to "createReactClass"
      "pragma": "React",  // Pragma to use, default to "React"
      "fragment": "Fragment",  // Fragment to use (may be a property of <pragma>), default to "Fragment"
      "version": "detect", // React version. "detect" automatically picks the version you have installed.
                           // You can also use `16.0`, `16.3`, etc, if you want to override the detected value.
                           // Defaults to the "defaultVersion" setting and warns if missing, and to "detect" in the future
      "defaultVersion": "", // Default React version to use when the version you have installed cannot be detected.
                            // If not provided, defaults to the latest React version.
      "flowVersion": "0.53" // Flow version
    },
    "propWrapperFunctions": [
        // The names of any function used to wrap propTypes, e.g. `forbidExtraProps`. If this isn't set, any propTypes wrapped in a function will be skipped.
        "forbidExtraProps",
        {"property": "freeze", "object": "Object"},
        {"property": "myFavoriteWrapper"},
        // for rules that check exact prop wrappers
        {"property": "forbidExtraProps", "exact": true}
    ],
    "componentWrapperFunctions": [
        // The name of any function used to wrap components, e.g. Mobx `observer` function. If this isn't set, components wrapped by these functions will be skipped.
        "observer", // `property`
        {"property": "styled"}, // `object` is optional
        {"property": "observer", "object": "Mobx"},
        {"property": "observer", "object": "<pragma>"} // sets `object` to whatever value `settings.react.pragma` is set to
    ],
    "formComponents": [
      // Components used as alternatives to <form> for forms, eg. <Form endpoint={ url } />
      "CustomForm",
      {"name": "SimpleForm", "formAttribute": "endpoint"},
      {"name": "Form", "formAttribute": ["registerEndpoint", "loginEndpoint"]}, // allows specifying multiple properties if necessary
    ],
    "linkComponents": [
      // Components used as alternatives to <a> for linking, eg. <Link to={ url } />
      "Hyperlink",
      {"name": "MyLink", "linkAttribute": "to"},
      {"name": "Link", "linkAttribute": ["to", "href"]}, // allows specifying multiple properties if necessary
    ]
  }
}

If you do not use a preset you will need to specify individual rules and add extra configuration.

Add "react" to the plugins section.

{
  "plugins": [
    "react"
  ]
}

Enable JSX support.

With eslint 2+

{
  "parserOptions": {
    "ecmaFeatures": {
      "jsx": true
    }
  }
}

Enable the rules that you would like to use.

  "rules": {
    "react/jsx-uses-react": "error",
    "react/jsx-uses-vars": "error",
  }

Shareable configs

Recommended

This plugin exports a recommended configuration that enforces React good practices.

To enable this configuration use the extends property in your .eslintrc config file:

{
  "extends": ["eslint:recommended", "plugin:react/recommended"]
}

See eslint documentation for more information about extending configuration files.

All

This plugin also exports an all configuration that includes every available rule. This pairs well with the eslint:all rule.

{
  "plugins": [
    "react"
  ],
  "extends": ["eslint:all", "plugin:react/all"]
}

Note: These configurations will import eslint-plugin-react and enable JSX in parser options.

Configuration (new: eslint.config.js)

From v8.21.0, eslint announced a new config system. In the new system, .eslintrc* is no longer used. eslint.config.js would be the default config file name. In eslint v8, the legacy system (.eslintrc*) would still be supported, while in eslint v9, only the new system would be supported.

And from v8.23.0, eslint CLI starts to look up eslint.config.js. So, if your eslint is >=8.23.0, you're 100% ready to use the new config system.

You might want to check out the official blog posts,

• https://eslint.org/blog/2022/08/new-config-system-part-1/
• https://eslint.org/blog/2022/08/new-config-system-part-2/
• https://eslint.org/blog/2022/08/new-config-system-part-3/

and the official docs.

Plugin

The default export of eslint-plugin-react is a plugin object.

const react = require('eslint-plugin-react');
const globals = require('globals');

module.exports = [
  …
  {
    files: ['**/*.{js,jsx,mjs,cjs,ts,tsx}'],
    plugins: {
      react,
    },
    languageOptions: {
      parserOptions: {
        ecmaFeatures: {
          jsx: true,
        },
      },
      globals: {
        ...globals.browser,
      },
    },
    rules: {
      // ... any rules you want
      'react/jsx-uses-react': 'error',
      'react/jsx-uses-vars': 'error',
     },
    // ... others are omitted for brevity
  },
  …
];

Configuring shared settings

Refer to the official docs.

The schema of the settings.react object would be identical to that of what's already described above in the legacy config section.

Flat Configs

This plugin exports 3 flat configs:

• flat.all
• flat.recommended
• flat['jsx-runtime']

The flat configs are available via the root plugin import. They will configure the plugin under the react/ namespace and enable JSX in languageOptions.parserOptions.

const reactPlugin = require('eslint-plugin-react');

module.exports = [
  …
  reactPlugin.configs.flat.recommended, // This is not a plugin object, but a shareable config object
  reactPlugin.configs.flat['jsx-runtime'], // Add this if you are using React 17+
  …
];

You can of course add/override some properties.

Note: Our shareable configs does not preconfigure files or languageOptions.globals. For most of the cases, you probably want to configure some properties by yourself.

const reactPlugin = require('eslint-plugin-react');
const globals = require('globals');

module.exports = [
  …
  {
    files: ['**/*.{js,mjs,cjs,jsx,mjsx,ts,tsx,mtsx}'],
    ...reactPlugin.configs.flat.recommended,
    languageOptions: {
      ...reactPlugin.configs.flat.recommended.languageOptions,
      globals: {
        ...globals.serviceworker,
        ...globals.browser,
      },
    },
  },
  …
];

The above example is same as the example below, as the new config system is based on chaining.

const reactPlugin = require('eslint-plugin-react');
const globals = require('globals');

module.exports = [
  …
  {
    files: ['**/*.{js,mjs,cjs,jsx,mjsx,ts,tsx,mtsx}'],
    ...reactPlugin.configs.flat.recommended,
  },
  {
    files: ['**/*.{js,mjs,cjs,jsx,mjsx,ts,tsx,mtsx}'],
    languageOptions: {
      globals: {
        ...globals.serviceworker,
        ...globals.browser,
      },
    },
  },
  …
];

List of supported rules

💼 Configurations enabled in.
🚫 Configurations disabled in.
🏃 Set in the jsx-runtime configuration.
☑️ Set in the recommended configuration.
🔧 Automatically fixable by the --fix CLI option.
💡 Manually fixable by editor suggestions.
❌ Deprecated.

Name	Description	💼	🚫	🔧	💡	❌
boolean-prop-naming	Enforces consistent naming for boolean props
button-has-type	Disallow usage of button elements without an explicit type attribute
checked-requires-onchange-or-readonly	Enforce using onChange or readonly attribute when checked is used
default-props-match-prop-types	Enforce all defaultProps have a corresponding non-required PropType
destructuring-assignment	Enforce consistent usage of destructuring assignment of props, state, and context			🔧
display-name	Disallow missing displayName in a React component definition	☑️
forbid-component-props	Disallow certain props on components
forbid-dom-props	Disallow certain props on DOM Nodes
forbid-elements	Disallow certain elements
forbid-foreign-prop-types	Disallow using another component's propTypes
forbid-prop-types	Disallow certain propTypes
forward-ref-uses-ref	Require all forwardRef components include a ref parameter				💡
function-component-definition	Enforce a specific function type for function components			🔧
hook-use-state	Ensure destructuring and symmetric naming of useState hook value and setter variables				💡
iframe-missing-sandbox	Enforce sandbox attribute on iframe elements
jsx-boolean-value	Enforce boolean attributes notation in JSX			🔧
jsx-child-element-spacing	Enforce or disallow spaces inside of curly braces in JSX attributes and expressions
jsx-closing-bracket-location	Enforce closing bracket location in JSX			🔧
jsx-closing-tag-location	Enforce closing tag location for multiline JSX			🔧
jsx-curly-brace-presence	Disallow unnecessary JSX expressions when literals alone are sufficient or enforce JSX expressions on literals in JSX children or attributes			🔧
jsx-curly-newline	Enforce consistent linebreaks in curly braces in JSX attributes and expressions			🔧
jsx-curly-spacing	Enforce or disallow spaces inside of curly braces in JSX attributes and expressions			🔧
jsx-equals-spacing	Enforce or disallow spaces around equal signs in JSX attributes			🔧
jsx-filename-extension	Disallow file extensions that may contain JSX
jsx-first-prop-new-line	Enforce proper position of the first property in JSX			🔧
jsx-fragments	Enforce shorthand or standard form for React fragments			🔧
jsx-handler-names	Enforce event handler naming conventions in JSX
jsx-indent	Enforce JSX indentation			🔧
jsx-indent-props	Enforce props indentation in JSX			🔧
jsx-key	Disallow missing key props in iterators/collection literals	☑️
jsx-max-depth	Enforce JSX maximum depth
jsx-max-props-per-line	Enforce maximum of props on a single line in JSX			🔧
jsx-newline	Require or prevent a new line after jsx elements and expressions.			🔧
jsx-no-bind	Disallow .bind() or arrow functions in JSX props
jsx-no-comment-textnodes	Disallow comments from being inserted as text nodes	☑️
jsx-no-constructed-context-values	Disallows JSX context provider values from taking values that will cause needless rerenders
jsx-no-duplicate-props	Disallow duplicate properties in JSX	☑️
jsx-no-leaked-render	Disallow problematic leaked values from being rendered			🔧
jsx-no-literals	Disallow usage of string literals in JSX
jsx-no-script-url	Disallow usage of javascript: URLs
jsx-no-target-blank	Disallow target="_blank" attribute without rel="noreferrer"	☑️		🔧
jsx-no-undef	Disallow undeclared variables in JSX	☑️
jsx-no-useless-fragment	Disallow unnecessary fragments			🔧
jsx-one-expression-per-line	Require one JSX element per line			🔧
jsx-pascal-case	Enforce PascalCase for user-defined JSX components
jsx-props-no-multi-spaces	Disallow multiple spaces between inline JSX props			🔧
jsx-props-no-spread-multi	Disallow JSX prop spreading the same identifier multiple times
jsx-props-no-spreading	Disallow JSX prop spreading
jsx-sort-default-props	Enforce defaultProps declarations alphabetical sorting					❌
jsx-sort-props	Enforce props alphabetical sorting			🔧
jsx-space-before-closing	Enforce spacing before closing bracket in JSX			🔧		❌
jsx-tag-spacing	Enforce whitespace in and around the JSX opening and closing brackets			🔧
jsx-uses-react	Disallow React to be incorrectly marked as unused	☑️	🏃
jsx-uses-vars	Disallow variables used in JSX to be incorrectly marked as unused	☑️
jsx-wrap-multilines	Disallow missing parentheses around multiline JSX			🔧
no-access-state-in-setstate	Disallow when this.state is accessed within setState
no-adjacent-inline-elements	Disallow adjacent inline elements not separated by whitespace.
no-array-index-key	Disallow usage of Array index in keys
no-arrow-function-lifecycle	Lifecycle methods should be methods on the prototype, not class fields			🔧
no-children-prop	Disallow passing of children as props	☑️
no-danger	Disallow usage of dangerous JSX properties
no-danger-with-children	Disallow when a DOM element is using both children and dangerouslySetInnerHTML	☑️
no-deprecated	Disallow usage of deprecated methods	☑️
no-did-mount-set-state	Disallow usage of setState in componentDidMount
no-did-update-set-state	Disallow usage of setState in componentDidUpdate
no-direct-mutation-state	Disallow direct mutation of this.state	☑️
no-find-dom-node	Disallow usage of findDOMNode	☑️
no-invalid-html-attribute	Disallow usage of invalid attributes				💡
no-is-mounted	Disallow usage of isMounted	☑️
no-multi-comp	Disallow multiple component definition per file
no-namespace	Enforce that namespaces are not used in React elements
no-object-type-as-default-prop	Disallow usage of referential-type variables as default param in functional component
no-redundant-should-component-update	Disallow usage of shouldComponentUpdate when extending React.PureComponent
no-render-return-value	Disallow usage of the return value of ReactDOM.render	☑️
no-set-state	Disallow usage of setState
no-string-refs	Disallow using string references	☑️
no-this-in-sfc	Disallow this from being used in stateless functional components
no-typos	Disallow common typos
no-unescaped-entities	Disallow unescaped HTML entities from appearing in markup	☑️			💡
no-unknown-property	Disallow usage of unknown DOM property	☑️		🔧
no-unsafe	Disallow usage of unsafe lifecycle methods		☑️
no-unstable-nested-components	Disallow creating unstable components inside components
no-unused-class-component-methods	Disallow declaring unused methods of component class
no-unused-prop-types	Disallow definitions of unused propTypes
no-unused-state	Disallow definitions of unused state
no-will-update-set-state	Disallow usage of setState in componentWillUpdate
prefer-es6-class	Enforce ES5 or ES6 class for React Components
prefer-exact-props	Prefer exact proptype definitions
prefer-read-only-props	Enforce that props are read-only			🔧
prefer-stateless-function	Enforce stateless components to be written as a pure function
prop-types	Disallow missing props validation in a React component definition	☑️
react-in-jsx-scope	Disallow missing React when using JSX	☑️	🏃
require-default-props	Enforce a defaultProps definition for every prop that is not a required prop
require-optimization	Enforce React components to have a shouldComponentUpdate method
require-render-return	Enforce ES5 or ES6 class for returning value in render function	☑️
self-closing-comp	Disallow extra closing tags for components without children			🔧
sort-comp	Enforce component methods order
sort-default-props	Enforce defaultProps declarations alphabetical sorting
sort-prop-types	Enforce propTypes declarations alphabetical sorting			🔧
state-in-constructor	Enforce class component state initialization style
static-property-placement	Enforces where React component static properties should be positioned.
style-prop-object	Enforce style prop value is an object
void-dom-elements-no-children	Disallow void DOM elements (e.g. <img />, <br />) from receiving children

Other useful plugins

• Rules of Hooks: eslint-plugin-react-hooks
• JSX accessibility: eslint-plugin-jsx-a11y
• React Native: eslint-plugin-react-native

License

eslint-plugin-react is licensed under the MIT License.