biome-config-expo

Shareable Biome config for Expo projects. A Biome equivalent of eslint-config-expo.

Includes React Native globals, JSX automatic runtime, React Hooks rules, and sensible defaults for TypeScript — so you don't have to configure them yourself.

Install

npm install -D biome-config-expo @biomejs/biome

Usage

Create a biome.json in your project root:

{
  "$schema": "https://biomejs.dev/schemas/2.4.4/schema.json",
  "extends": ["biome-config-expo/biome.json"]
}

Override anything you need:

{
  "$schema": "https://biomejs.dev/schemas/2.4.4/schema.json",
  "extends": ["biome-config-expo/biome.json"],
  "formatter": {
    "lineWidth": 120
  }
}

What's Included

Globals — __DEV__, fetch, FormData, XMLHttpRequest, requestAnimationFrame, alert, navigator, window, process, and others from the React Native environment. Config files (*.config.js, metro.config.*) also get Node.js globals.

Linter — All Biome recommended rules, plus rules mapped from eslint-config-expo:

• React Hooks: useExhaustiveDependencies, useHookAtTopLevel
• Correctness: noUnusedVariables, noUnusedImports, useIsNan, useJsxKeyInIterable
• Suspicious: noDoubleEquals, noDuplicateObjectKeys, noDuplicateJsxProps, noVar
• Style: useConst, useConsistentArrayType, useImportType
• Complexity: noUselessConstructor, useOptionalChain

Formatter — 2-space indentation, 100 character line width, Biome defaults for everything else.

JSX Runtime — Set to transparent (React 17+ automatic transform), matching Expo's default.

License

MIT