--- title: ESLint Plugin nav_title: ESLint description: Learn how to use and configure the ESLint plugin to catch common issues and problems in a Next.js application. --- {/* The content of this doc is shared between the app and pages router. You can use the `Content` component to add content that is specific to the Pages Router. Any shared content should not be wrapped in a component. */} Next.js provides an ESLint plugin, [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next), already bundled within the base configuration that makes it possible to catch common issues and problems in a Next.js application. ## Reference Recommended rule-sets from the following ESLint plugins are all used within `eslint-config-next`: - [`eslint-plugin-react`](https://www.npmjs.com/package/eslint-plugin-react) - [`eslint-plugin-react-hooks`](https://www.npmjs.com/package/eslint-plugin-react-hooks) - [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next) This will take precedence over the configuration from `next.config.js`. ### Rules The full set of rules is as follows: | Enabled in recommended config | Rule | Description | | :---------------------------: | ------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------- | | | [@next/next/google-font-display](/docs/messages/google-font-display) | Enforce font-display behavior with Google Fonts. | | | [@next/next/google-font-preconnect](/docs/messages/google-font-preconnect) | Ensure `preconnect` is used with Google Fonts. | | | [@next/next/inline-script-id](/docs/messages/inline-script-id) | Enforce `id` attribute on `next/script` components with inline content. | | | [@next/next/next-script-for-ga](/docs/messages/next-script-for-ga) | Prefer `next/script` component when using the inline script for Google Analytics. | | | [@next/next/no-assign-module-variable](/docs/messages/no-assign-module-variable) | Prevent assignment to the `module` variable. | | | [@next/next/no-async-client-component](/docs/messages/no-async-client-component) | Prevent Client Components from being async functions. | | | [@next/next/no-before-interactive-script-outside-document](/docs/messages/no-before-interactive-script-outside-document) | Prevent usage of `next/script`'s `beforeInteractive` strategy outside of `pages/_document.js`. | | | [@next/next/no-css-tags](/docs/messages/no-css-tags) | Prevent manual stylesheet tags. | | | [@next/next/no-document-import-in-page](/docs/messages/no-document-import-in-page) | Prevent importing `next/document` outside of `pages/_document.js`. | | | [@next/next/no-duplicate-head](/docs/messages/no-duplicate-head) | Prevent duplicate usage of `` in `pages/_document.js`. | | | [@next/next/no-head-element](/docs/messages/no-head-element) | Prevent usage of `` element. | | | [@next/next/no-head-import-in-document](/docs/messages/no-head-import-in-document) | Prevent usage of `next/head` in `pages/_document.js`. | | | [@next/next/no-html-link-for-pages](/docs/messages/no-html-link-for-pages) | Prevent usage of `` elements to navigate to internal Next.js pages. | | | [@next/next/no-img-element](/docs/messages/no-img-element) | Prevent usage of `` element due to slower LCP and higher bandwidth. | | | [@next/next/no-page-custom-font](/docs/messages/no-page-custom-font) | Prevent page-only custom fonts. | | | [@next/next/no-script-component-in-head](/docs/messages/no-script-component-in-head) | Prevent usage of `next/script` in `next/head` component. | | | [@next/next/no-styled-jsx-in-document](/docs/messages/no-styled-jsx-in-document) | Prevent usage of `styled-jsx` in `pages/_document.js`. | | | [@next/next/no-sync-scripts](/docs/messages/no-sync-scripts) | Prevent synchronous scripts. | | | [@next/next/no-title-in-document-head](/docs/messages/no-title-in-document-head) | Prevent usage of `` with `Head` component from `next/document`. | | <Check size={18} /> | @next/next/no-typos | Prevent common typos in [Next.js's data fetching functions](/docs/pages/building-your-application/data-fetching) | | <Check size={18} /> | [@next/next/no-unwanted-polyfillio](/docs/messages/no-unwanted-polyfillio) | Prevent duplicate polyfills from Polyfill.io. | We recommend using an appropriate [integration](https://eslint.org/docs/user-guide/integrations#editors) to view warnings and errors directly in your code editor during development. ## Examples ### Linting custom directories and files By default, Next.js will run ESLint for all files in the `pages/`, `app/`, `components/`, `lib/`, and `src/` directories. However, you can specify which directories using the `dirs` option in the `eslint` config in `next.config.js` for production builds: ```js filename="next.config.js" module.exports = { eslint: { dirs: ['pages', 'utils'], // Only run ESLint on the 'pages' and 'utils' directories during production builds (next build) }, } ``` Similarly, the `--dir` and `--file` flags can be used for `next lint` to lint specific directories and files: ```bash filename="Terminal" next lint --dir pages --dir utils --file bar.js ``` ### Specifying a root directory within a monorepo If you're using `eslint-plugin-next` in a project where Next.js isn't installed in your root directory (such as a monorepo), you can tell `eslint-plugin-next` where to find your Next.js application using the `settings` property in your `.eslintrc`: ```js filename="eslint.config.mjs" import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, }) const eslintConfig = [ ...compat.config({ extends: ['next'], settings: { next: { rootDir: 'packages/my-app/', }, }, }), ] export default eslintConfig ``` `rootDir` can be a path (relative or absolute), a glob (i.e. `"packages/*/"`), or an array of paths and/or globs. ### Disabling the cache To improve performance, information of files processed by ESLint are cached by default. This is stored in `.next/cache` or in your defined [build directory](/docs/app/api-reference/config/next-config-js/distDir). If you include any ESLint rules that depend on more than the contents of a single source file and need to disable the cache, use the `--no-cache` flag with `next lint`. ```bash filename="Terminal" next lint --no-cache ``` ### Disabling rules If you would like to modify or disable any rules provided by the supported plugins (`react`, `react-hooks`, `next`), you can directly change them using the `rules` property in your `.eslintrc`: ```js filename="eslint.config.mjs" import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, }) const eslintConfig = [ ...compat.config({ extends: ['next'], rules: { 'react/no-unescaped-entities': 'off', '@next/next/no-page-custom-font': 'off', }, }), ] export default eslintConfig ``` ### With Core Web Vitals The `next/core-web-vitals` rule set is enabled when `next lint` is run for the first time and the **strict** option is selected. ```js filename="eslint.config.mjs" import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, }) const eslintConfig = [ ...compat.config({ extends: ['next/core-web-vitals'], }), ] export default eslintConfig ``` `next/core-web-vitals` updates `eslint-plugin-next` to error on a number of rules that are warnings by default if they affect [Core Web Vitals](https://web.dev/vitals/). > The `next/core-web-vitals` entry point is automatically included for new applications built with [Create Next App](/docs/app/api-reference/cli/create-next-app). ### With TypeScript In addition to the Next.js ESLint rules, `create-next-app --typescript` will also add TypeScript-specific lint rules with `next/typescript` to your config: ```js filename="eslint.config.mjs" import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, }) const eslintConfig = [ ...compat.config({ extends: ['next/core-web-vitals', 'next/typescript'], }), ] export default eslintConfig ``` Those rules are based on [`plugin:@typescript-eslint/recommended`](https://typescript-eslint.io/linting/configs#recommended). See [typescript-eslint > Configs](https://typescript-eslint.io/linting/configs) for more details. ### With Prettier ESLint also contains code formatting rules, which can conflict with your existing [Prettier](https://prettier.io/) setup. We recommend including [eslint-config-prettier](https://github.com/prettier/eslint-config-prettier) in your ESLint config to make ESLint and Prettier work together. First, install the dependency: ```bash filename="Terminal" npm install --save-dev eslint-config-prettier yarn add --dev eslint-config-prettier pnpm add --save-dev eslint-config-prettier bun add --dev eslint-config-prettier ``` Then, add `prettier` to your existing ESLint config: ```js filename="eslint.config.mjs" import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, }) const eslintConfig = [ ...compat.config({ extends: ['next', 'prettier'], }), ] export default eslintConfig ``` ### Running lint on staged files If you would like to use `next lint` with [lint-staged](https://github.com/okonet/lint-staged) to run the linter on staged git files, you'll have to add the following to the `.lintstagedrc.js` file in the root of your project in order to specify usage of the `--file` flag. ```js filename=".lintstagedrc.js" const path = require('path') const buildEslintCommand = (filenames) => `next lint --fix --file ${filenames .map((f) => path.relative(process.cwd(), f)) .join(' --file ')}` module.exports = { '*.{js,jsx,ts,tsx}': [buildEslintCommand], } ``` ## Disabling linting during production builds If you do not want ESLint to run during `next build`, you can set the `eslint.ignoreDuringBuilds` option in `next.config.js` to `true`: ```ts filename="next.config.ts" switcher import type { NextConfig } from 'next' const nextConfig: NextConfig = { eslint: { // Warning: This allows production builds to successfully complete even if // your project has ESLint errors. ignoreDuringBuilds: true, }, } export default nextConfig ``` ```js filename="next.config.js" switcher const nextConfig = { eslint: { // Warning: This allows production builds to successfully complete even if // your project has ESLint errors. ignoreDuringBuilds: true, }, } export default nextConfig ``` ### Migrating existing config If you already have ESLint configured in your application, we recommend extending from this plugin directly instead of including `eslint-config-next` unless a few conditions are met. #### Recommended plugin ruleset If the following conditions are true: - You have one or more of the following plugins already installed (either separately or through a different config such as `airbnb` or `react-app`): - `react` - `react-hooks` - `jsx-a11y` - `import` - You've defined specific `parserOptions` that are different from how Babel is configured within Next.js (this is not recommended unless you have [customized your Babel configuration](/docs/pages/guides/babel)) - You have `eslint-plugin-import` installed with Node.js and/or TypeScript [resolvers](https://github.com/benmosher/eslint-plugin-import#resolvers) defined to handle imports Then we recommend either removing these settings if you prefer how these properties have been configured within [`eslint-config-next`](https://github.com/vercel/next.js/blob/canary/packages/eslint-config-next/index.js) or extending directly from the Next.js ESLint plugin instead: ```js module.exports = { extends: [ //... 'plugin:@next/next/recommended', ], } ``` The plugin can be installed normally in your project without needing to run `next lint`: ```bash filename="Terminal" npm install --save-dev @next/eslint-plugin-next yarn add --dev @next/eslint-plugin-next pnpm add --save-dev @next/eslint-plugin-next bun add --dev @next/eslint-plugin-next ``` This eliminates the risk of collisions or errors that can occur due to importing the same plugin or parser across multiple configurations. #### Additional configurations If you already use a separate ESLint configuration and want to include `eslint-config-next`, ensure that it is extended last after other configurations. For example: ```js filename="eslint.config.mjs" import js from '@eslint/js' import { FlatCompat } from '@eslint/eslintrc' const compat = new FlatCompat({ // import.meta.dirname is available after Node.js v20.11.0 baseDirectory: import.meta.dirname, recommendedConfig: js.configs.recommended, }) const eslintConfig = [ ...compat.config({ extends: ['eslint:recommended', 'next'], }), ] export default eslintConfig ``` The `next` configuration already handles setting default values for the `parser`, `plugins` and `settings` properties. There is no need to manually re-declare any of these properties unless you need a different configuration for your use case. If you include any other shareable configurations, **you will need to make sure that these properties are not overwritten or modified**. Otherwise, we recommend removing any configurations that share behavior with the `next` configuration or extending directly from the Next.js ESLint plugin as mentioned above.