@antfu/eslint-config

• Auto fix for formatting (aimed to be used standalone without Prettier)
• Reasonable defaults, best practices, only one line of config
• Designed to work with TypeScript, JSX, Vue, JSON, YAML, Toml, Markdown, etc. Out-of-box.
• Opinionated, but very customizable
• ESLint Flat config, compose easily!
• Optional React, Next.js, Svelte, UnoCSS, Astro, Solid support
• Optional formatters support for formatting CSS, HTML, XML, etc.
• Style principle: Minimal for reading, stable for diff, consistent
  • Sorted imports, dangling commas
  • Single quotes, no semi
  • Using ESLint Stylistic
• Respects .gitignore by default
• Requires ESLint v9.5.0+

[!WARNING] I am super appreciative and even a bit flattered that so many of you are fond of using this config. For that reason, I tried to make it as flexible and customizable as possible to fit more use cases.

However, please keep in mind that this is still a personal config with a lot of opinions. Changes might not always work for everyone and every use case.

If you are using this config directly, I suggest you review the changes every time you update. Or if you want more control over the rules, always feel free to fork it. Thanks!

[!TIP] If you are interested in the tooling and the philosophy behind this config, I gave a talk about ESLint flat config at JSNation 2024 - ESLint One for All Made Easy, slides are here.

Usage

Starter Wizard

We provided a CLI tool to help you set up your project, or migrate from the legacy config to the new flat config with one command.

pnpm dlx @antfu/eslint-config@latest

Manual Install

If you prefer to set up manually:

pnpm i -D eslint @antfu/eslint-config

And create eslint.config.mjs in your project root:

// eslint.config.mjs
import antfu from '@antfu/eslint-config'

export default antfu()

If you still use some configs from the legacy eslintrc format, you can use the @eslint/eslintrc package to convert them to the flat config.

// eslint.config.mjs
import antfu from '@antfu/eslint-config'
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat()

export default antfu(
  {
    ignores: [],
  },

  // Legacy config
  ...compat.config({
    extends: [
      'eslint:recommended',
      // Other extends...
    ],
  })

  // Other flat configs...
)

Note that .eslintignore no longer works in Flat config, see customization for more details.

Add script for package.json

For example:

{
  "scripts": {
    "lint": "eslint",
    "lint:fix": "eslint --fix"
  }
}

IDE Support (auto fix on save)

Install VS Code ESLint extension

Add the following settings to your .vscode/settings.json:

{
  // Disable the default formatter, use eslint instead
  "prettier.enable": false,
  "editor.formatOnSave": false,

  // Auto fix
  "editor.codeActionsOnSave": {
    "source.fixAll.eslint": "explicit",
    "source.organizeImports": "never"
  },

  // Silent the stylistic rules in your IDE, but still auto fix them
  "eslint.rules.customizations": [
    { "rule": "style/*", "severity": "off", "fixable": true },
    { "rule": "format/*", "severity": "off", "fixable": true },
    { "rule": "*-indent", "severity": "off", "fixable": true },
    { "rule": "*-spacing", "severity": "off", "fixable": true },
    { "rule": "*-spaces", "severity": "off", "fixable": true },
    { "rule": "*-order", "severity": "off", "fixable": true },
    { "rule": "*-dangle", "severity": "off", "fixable": true },
    { "rule": "*-newline", "severity": "off", "fixable": true },
    { "rule": "*quotes", "severity": "off", "fixable": true },
    { "rule": "*semi", "severity": "off", "fixable": true }
  ],

  // Enable eslint for all supported languages
  "eslint.validate": [
    "javascript",
    "javascriptreact",
    "typescript",
    "typescriptreact",
    "vue",
    "html",
    "markdown",
    "json",
    "jsonc",
    "yaml",
    "toml",
    "xml",
    "gql",
    "graphql",
    "astro",
    "svelte",
    "css",
    "less",
    "scss",
    "pcss",
    "postcss"
  ]
}

Add the following settings to your .zed/settings.json:

{
  // Use ESLint's --fix:
  "code_actions_on_format": {
    "source.fixAll.eslint": true
  },
  "formatter": [],
  // Enable eslint for all supported languages
  // Defaults only include https://github.com/search?q=repo%3Azed-industries%2Fzed%20eslint_languages&type=code
  "languages": {
    "HTML": {
      "language_servers": ["...", "eslint"]
    },
    "Markdown": {
      "language_servers": ["...", "eslint"]
    },
    "Markdown-Inline": {
      "language_servers": ["...", "eslint"]
    },
    "JSON": {
      "language_servers": ["...", "eslint"]
    },
    "JSONC": {
      "language_servers": ["...", "eslint"]
    },
    "YAML": {
      "language_servers": ["...", "eslint"]
    },
    "CSS": {
      "language_servers": ["...", "eslint"]
    }
    // Add other languages as needed
  },
  "lsp": {
    "eslint": {
      "settings": {
        "workingDirectories": ["./"],

        // Silent the stylistic rules in your IDE, but still auto fix them
        "rulesCustomizations": [
          { "rule": "style/*", "severity": "off", "fixable": true },
          { "rule": "format/*", "severity": "off", "fixable": true },
          { "rule": "*-indent", "severity": "off", "fixable": true },
          { "rule": "*-spacing", "severity": "off", "fixable": true },
          { "rule": "*-spaces", "severity": "off", "fixable": true },
          { "rule": "*-order", "severity": "off", "fixable": true },
          { "rule": "*-dangle", "severity": "off", "fixable": true },
          { "rule": "*-newline", "severity": "off", "fixable": true },
          { "rule": "*quotes", "severity": "off", "fixable": true },
          { "rule": "*semi", "severity": "off", "fixable": true }
        ]
      }
    }
  }
}

Update your configuration to use the following:

local customizations = {
  { rule = 'style/*', severity = 'off', fixable = true },
  { rule = 'format/*', severity = 'off', fixable = true },
  { rule = '*-indent', severity = 'off', fixable = true },
  { rule = '*-spacing', severity = 'off', fixable = true },
  { rule = '*-spaces', severity = 'off', fixable = true },
  { rule = '*-order', severity = 'off', fixable = true },
  { rule = '*-dangle', severity = 'off', fixable = true },
  { rule = '*-newline', severity = 'off', fixable = true },
  { rule = '*quotes', severity = 'off', fixable = true },
  { rule = '*semi', severity = 'off', fixable = true },
}

local lspconfig = require('lspconfig')
-- Enable eslint for all supported languages
lspconfig.eslint.setup(
  {
    filetypes = {
      "javascript",
      "javascriptreact",
      "javascript.jsx",
      "typescript",
      "typescriptreact",
      "typescript.tsx",
      "vue",
      "html",
      "markdown",
      "json",
      "jsonc",
      "yaml",
      "toml",
      "xml",
      "gql",
      "graphql",
      "astro",
      "svelte",
      "css",
      "less",
      "scss",
      "pcss",
      "postcss"
    },
    settings = {
      -- Silent the stylistic rules in your IDE, but still auto fix them
      rulesCustomizations = customizations,
    },
  }
)

Neovim format on save

There's few ways you can achieve format on save in neovim:

• nvim-lspconfig has a EslintFixAll command predefined, you can create a autocmd to call this command after saving file.

lspconfig.eslint.setup({
  --- ...
  on_attach = function(client, bufnr)
    vim.api.nvim_create_autocmd("BufWritePre", {
      buffer = bufnr,
      command = "EslintFixAll",
    })
  end,
})

• Use conform.nvim.
• Use none-ls
• Use nvim-lint

Customization

Since v1.0, we migrated to ESLint Flat config. It provides much better organization and composition.

Normally you only need to import the antfu preset:

// eslint.config.js
import antfu from '@antfu/eslint-config'

export default antfu()

And that's it! Or you can configure each integration individually, for example:

// eslint.config.js
import antfu from '@antfu/eslint-config'

export default antfu({
  // Type of the project. 'lib' for libraries, the default is 'app'
  type: 'lib',

  // `.eslintignore` is no longer supported in Flat config, use `ignores` instead
  // The `ignores` option in the option (first argument) is specifically treated to always be global ignores
  // And will **extend** the config's default ignores, not override them
  // You can also pass a function to modify the default ignores
  ignores: [
    '**/fixtures',
    // ...globs
  ],

  // Parse the `.gitignore` file to get the ignores, on by default
  gitignore: true,

  // Enable stylistic formatting rules
  // stylistic: true,

  // Or customize the stylistic rules
  stylistic: {
    indent: 2, // 4, or 'tab'
    quotes: 'single', // or 'double'
    braceStyle: 'stroustrup', // '1tbs', or 'allman'
  },

  // TypeScript and Vue are autodetected, you can also explicitly enable them:
  typescript: true,
  vue: true,

  // Disable jsonc and yaml support
  jsonc: false,
  yaml: false,
})

The antfu factory function also accepts any number of arbitrary custom config overrides:

// eslint.config.js
import antfu from '@antfu/eslint-config'

export default antfu(
  {
    // Configures for antfu's config
  },

  // From the second arguments they are ESLint Flat Configs
  // you can have multiple configs
  {
    files: ['**/*.ts'],
    rules: {},
  },
  {
    rules: {},
  },
)

Going more advanced, you can also import fine-grained configs and compose them as you wish:

We wouldn't recommend using this style in general unless you know exactly what they are doing, as there are shared options between configs and might need extra care to make them consistent.

// eslint.config.js
import {
  combine,
  comments,
  ignores,
  imports,
  javascript,
  jsdoc,
  jsonc,
  markdown,
  node,
  sortPackageJson,
  sortTsconfig,
  stylistic,
  toml,
  typescript,
  unicorn,
  vue,
  yaml,
} from '@antfu/eslint-config'

export default combine(
  ignores(),
  javascript(/* Options */),
  comments(),
  node(),
  jsdoc(),
  imports(),
  unicorn(),
  typescript(/* Options */),
  stylistic(),
  vue(),
  jsonc(),
  yaml(),
  toml(),
  markdown(),
)

Check out the configs and factory for more details.

Thanks to sxzz/eslint-config for the inspiration and reference.

Plugins Renaming

Since flat config requires us to explicitly provide the plugin names (instead of the mandatory convention from npm package name), we renamed some plugins to make the overall scope more consistent and easier to write.

When you want to override rules, or disable them inline, you need to update to the new prefix:

-// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+// eslint-disable-next-line ts/consistent-type-definitions
type foo = { bar: 2 }

[!NOTE] About plugin renaming - it is actually rather a dangerous move that might lead to potential naming collisions, pointed out here and here. As this config also very personal and opinionated, I ambitiously position this config as the only "top-level" config per project, that might pivots the taste of how rules are named.

This config cares more about the user-facings DX, and try to ease out the implementation details. For example, users could keep using the semantic import/order without ever knowing the underlying plugin has migrated twice to eslint-plugin-i and then to eslint-plugin-import-x. User are also not forced to migrate to the implicit i/order halfway only because we swapped the implementation to a fork.

That said, it's probably still not a good idea. You might not want to do this if you are maintaining your own eslint config.

Feel free to open issues if you want to combine this config with some other config presets but faced naming collisions. I am happy to figure out