@simonbiennier/eslint-config v1.0.8

@simonbiennier/eslint-config

Simon Biennier's ESLint config factory.

Usage

Starter wizard

nlx @simonbiennier/eslint-config@latest

Manual install

ni eslint @simonbiennier/eslint-config -D

Create eslint.config.mjs in project root:

// eslint.config.mjs
import config from "@simonbiennier/eslint-config"

export default config()

Add scripts to package.json:

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

VSCode support

Install VS Code ESLint extension

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

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

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

  "eslint.runtime": "node",

  // enable eslint for supported languages
  "eslint.validate": [
    "javascript",
    "javascriptreact",
    "typescript",
    "typescriptreact",
    "html",
    "markdown",
    "json",
    "json5",
    "jsonc",
    "yaml",
    "toml",
    "xml"
  ],

  // javascript and typescript settings
  "javascript.format.enable": false,
  "typescript.format.enable": false,
  "javascript.preferences.importModuleSpecifier": "relative",
  "typescript.preferences.importModuleSpecifier": "relative",
  "javascript.validate.enable": true,
  "typescript.validate.enable": true
}

Customisation

Simplest use case is to use the default config:

// eslint.config.js
import config from "@simonbiennier/eslint-config"

export default config()

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

// eslint.config.js
import config from "@simonbiennier/eslint-config"

export default config({
  // 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 is autodetected, you can also explicitly enable it:
  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 config factory function also accepts any number of arbitrary custom config overrides:

// eslint.config.js
import config from "@simonbiennier/eslint-config"

export default config(
  {
    // configures for 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 "@simonbiennier/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.

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 dangrous move that might leading 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.

Revert the plugin renaming by:

import config from "@simonbiennier/eslint-config"

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

Rules overrides

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

// eslint.config.js
import config from "@simonbiennier/eslint-config"

export default config(
  {
    typescript: true
  },
  {
    // remember to specify the file glob here, otherwise it might cause the x plugin to handle non-x files
    files: ["**/*.ts"],
    rules: {
      "ts/consistent-type-definitions": ["error", "interface"],
    },
  },
  {
    // 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 config from "@simonbiennier/eslint-config"

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

Config composer

The factory function config() 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 config from "@simonbiennier/eslint-config"

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

Optional configs

Some optional configs for specific use cases and their dependencies are not included 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 config from "@simonbiennier/eslint-config"

export default config({
  formatters: {
    /**
     * Format CSS, LESS, SCSS files
     * 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:

npm i -D eslint-plugin-format

React

To enable React support, you need to explicitly turn it on:

// eslint.config.js
import config from "@simonbiennier/eslint-config"

export default config({
  react: true,
})

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

ni -D @eslint-react/eslint-plugin eslint-plugin-react-hooks eslint-plugin-react-refresh

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 config from "@simonbiennier/eslint-config"

export default config({
  typescript: {
    tsconfigPath: "tsconfig.json",
  },
})

Editor specific disables

Auto-fixing for the following rules are disabled when ESLint is running in a code editor:

• prefer-const
• test/no-only-tests
• unused-imports/no-unused-imports

Since v3.16.0, they are no longer disabled, but made non-fixable using this helper.

This is to prevent unused imports from getting removed by the editor 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 config from "@simonbiennier/eslint-config"

export default config({
  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

npm 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