@adrianub/eslint-config

Adrián UB's ESLint config

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 @adrianub/eslint-config@latest

Manual Install

If you prefer to set up manually:

pnpm i -D eslint @adrianub/eslint-config

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

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

export default adrianub()

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 adrianub from '@adrianub/eslint-config'
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat()

export default adrianub(
  {
    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 you 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",
    "typescript",
    "html",
    "markdown",
    "json",
    "jsonc",
    "yaml",
    "toml",
    "xml",
    "gql",
    "graphql",
    "astro",
    "css",
    "less",
    "scss",
    "pcss",
    "postcss"
  ]
}

Customization

Normally you only need to import the adrianub preset:

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

export default adrianub()

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

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

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

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

  // Or customize the stylistic rules
  stylistic: {
    indent: 2, // 4, or 'tab'
    quotes: 'single', // or 'double'
  },

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

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

  // `.eslintignore` is no longer supported in Flat config, use `ignores` instead
  ignores: [
    '**/fixtures',
    // ...globs
  ]
})

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

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

export default adrianub(
  {
    // 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,
  yaml,
} from '@adrianub/eslint-config'

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

Check out the configs and factory for more details.

Thanks to antfu/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.

| New Prefix | Original Prefix | Source Plugin | | ------------ | ---------------------- | ------------------------------------------------------------------------------------------ | | import/* | import-x/* | eslint-plugin-import-x | | node/* | n/* | eslint-plugin-n | | yaml/* | yml/* | eslint-plugin-yml | | ts/* | @typescript-eslint/* | @typescript-eslint/eslint-plugin | | style/* | @stylistic/* | @stylistic/eslint-plugin | | test/* | vitest/* | @vitest/eslint-plugin | | test/* | no-only-tests/* | eslint-plugin-no-only-tests | | adrianub/* | antfu/* | eslint-plugin-antfu |

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 }

If you really want to use the original prefix, you can revert the plugin renaming by:

import adrianub from '@adrianub/eslint-config'

export default adrianub()
  .renamePlugins({
    ts: '@typescript-eslint',
    yaml: 'yml',
    node: 'n',
    // ...
  })

Rules Overrides

Certain rules would only be enabled in specific files, for example, ts/* rules would only be enabled in .ts. If you want to override the rules, you need to specify the file extension:

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

export default adrianub(
  {
    typescript: true
  },
  {
    // Without `files`, they are general rules for all files
    rules: {
      'style/semi': ['error', 'never'],
    },
  }
)

We also provided the overrides options in each integration to make it easier:

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

export default adrianub({
  typescript: {
    overrides: {
      'ts/consistent-type-definitions': ['error', 'interface'],
    },
  },
  yaml: {
    overrides: {
      // ...
    },
  },
})

Config Composer

The factory function antfu() returns a FlatConfigComposer object from eslint-flat-config-utils where you can chain the methods to compose the config even more flexibly.

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

export default adrianub()
  .prepend(
    // some configs before the main config
  )
  // overrides any named configs
  .override(
    'adrianub/imports',
    {
      rules: {
        'import/order': ['error', { 'newlines-between': 'always' }],
      }
    }
  )
  // rename plugin prefixes
  .renamePlugins({
    'old-prefix': 'new-prefix',
    // ...
  })
// ...

Optional Configs

We provide some optional configs for specific use cases, that we don't include their dependencies by default.

Formatters

Use external formatters to format files that ESLint cannot handle yet (.css, .html, etc). Powered by eslint-plugin-format.

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

export default adrianub({
  formatters: {
    /**
     * Format CSS, LESS, SCSS files, also the `<style>` blocks
     * By default uses Prettier
     */
    css: true,
    /**
     * Format HTML files
     * By default uses Prettier
     */
    html: true,
    /**
     * Format Markdown files
     * Supports Prettier and dprint
     * By default uses Prettier
     */
    markdown: 'prettier'
  }
})

Running npx eslint should prompt you to install the required dependencies, otherwise, you can install them manually:

pnpm i -D eslint-plugin-format

Optional Rules

This config also provides some optional plugins/rules for extended usage.

command

Powered by eslint-plugin-command. It is not a typical rule for linting, but an on-demand micro-codemod tool that triggers by specific comments.

For a few triggers, for example:

• /// to-function - converts an arrow function to a normal function
• /// to-arrow - converts a normal function to an arrow function
• /// to-for-each - converts a for-in/for-of loop to .forEach()
• /// to-for-of - converts a .forEach() to a for-of loop
• /// keep-sorted - sorts an object/array/interface
• ... etc. - refer to the documentation

You can add the trigger comment one line above the code you want to transform, for example (note the triple slash):

/// to-function
const foo = async (msg: string): void => {
  console.log(msg)
}

Will be transformed to this when you hit save with your editor or run eslint . --fix:

async function foo(msg: string): void {
  console.log(msg)
}

The command comments are usually one-off and will be removed along with the transformation.

Type Aware Rules

You can optionally enable the type aware rules by passing the options object to the typescript config:

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

export default adrianub({
  typescript: {
    tsconfigPath: 'tsconfig.json',
  },
})

Editor Specific Disables

Some rules are disabled when inside ESLint IDE integrations, namely unused-imports/no-unused-imports test/no-only-tests

This is to prevent unused imports from getting removed by the IDE during refactoring to get a better developer experience. Those rules will be applied when you run ESLint in the terminal or Lint Staged. If you don't want this behavior, you can disable them:

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

export default adrianub({
  isInEditor: false
})

Lint Staged

If you want to apply lint and auto-fix before every commit, you can add the following to your package.json:

{
  "simple-git-hooks": {
    "pre-commit": "pnpm lint-staged"
  },
  "lint-staged": {
    "*": "eslint --fix"
  }
}

and then

pnpm i -D lint-staged simple-git-hooks

// to active the hooks
npx simple-git-hooks

View what rules are enabled

I built a visual tool to help you view what rules are enabled in your project and apply them to what files, @eslint/config-inspector

Go to your project root that contains eslint.config.js and run:

npx @eslint/config-inspector

FAQ

Prettier?

Why I don't use Prettier

Well, you can still use Prettier to format files that are not supported well by ESLint yet, such as .css, .html, etc. See formatters for more details.

How to format CSS?

You can opt-in to the formatters feature to format your CSS. Note that it's only doing formatting, but not linting. If you want proper linting support, give stylelint a try.

Top-level Function Style, etc.

I am a very opinionated person, so as this config. I prefer the top-level functions always using the function declaration over arrow functions; I prefer one-line if statements without braces and always wraps, and so on. I even wrote some custom rules to enforce them.

I know they are not necessarily the popular opinions. If you really want to get rid of them, you can disable them with:

import adrianub from '@adrianub/eslint-config'

export default adrianub({
  lessOpinionated: true
})

I prefer XXX...

Sure, you can configure and override rules locally in your project to fit your needs. If that still does not work for you, you can always fork this repo and maintain your own.

Sponsors

License

MIT License © 2024-PRESENT Adrián UB