Biome Linting
Fast, unified linting and formatting (10-25x faster than ESLint + Prettier).
Why Biome in 2026
| Aspect | Biome | ESLint + Prettier |
|---|---|---|
| Speed | ~200ms for 10k lines | 3-5s |
| Config files | 1 (biome.json) | 4+ |
| npm packages | 1 binary | 127+ |
| Rules | 421 | Varies by plugins |
| Type inference | Yes (v2.0+) | Requires tsconfig |
Quick Start
bash
# Install npm install --save-dev --save-exact @biomejs/biome # Initialize npx @biomejs/biome init # Check (lint + format) npx @biomejs/biome check . # Fix npx @biomejs/biome check --write . # CI mode (fails on errors) npx @biomejs/biome ci .
Biome 2.0 Features
Type Inference: Reads .d.ts from node_modules for type-aware rules:
json
{
"linter": {
"rules": {
"nursery": {
"noFloatingPromises": "error" // Catches unhandled promises
}
}
}
}
Multi-file Analysis: Cross-module analysis for better diagnostics.
Basic Configuration
json
{
"$schema": "https://biomejs.dev/schemas/2.0.0/schema.json",
"formatter": {
"enabled": true,
"indentStyle": "space",
"indentWidth": 2,
"lineWidth": 100
},
"linter": {
"enabled": true,
"rules": {
"recommended": true,
"correctness": {
"noUnusedVariables": "error",
"noUnusedImports": "error"
},
"suspicious": {
"noExplicitAny": "warn"
}
}
},
"javascript": {
"formatter": {
"quoteStyle": "single",
"trailingCommas": "all"
}
}
}
ESLint Migration
bash
# Auto-migrate configuration npx @biomejs/biome migrate eslint --write
Common Rule Mappings:
| ESLint | Biome |
|---|---|
| no-unused-vars | correctness/noUnusedVariables |
| no-console | suspicious/noConsole |
| @typescript-eslint/* | Most supported |
| eslint-plugin-react | Most supported |
| eslint-plugin-jsx-a11y | Most supported |
CI Integration
yaml
# .github/workflows/lint.yml - uses: biomejs/setup-biome@v2 - run: biome ci .
Overrides for Gradual Adoption
json
{
"overrides": [
{
"include": ["*.test.ts", "*.spec.ts"],
"linter": {
"rules": {
"suspicious": { "noExplicitAny": "off" }
}
}
},
{
"include": ["legacy/**"],
"linter": { "enabled": false }
}
]
}
Key Decisions
| Decision | Recommendation |
|---|---|
| New vs migration | Biome first for new projects; migrate existing gradually |
| Config strictness | Start with recommended, tighten over time |
| CI strategy | Use biome ci for strict mode, biome check for local |
| Type inference | Enable for TypeScript projects (v2.0+) |
Related Skills
- •
vite-advanced- Build tooling integration - •
react-server-components-framework- React linting rules - •
ci-cd-engineer- CI pipeline setup
References
- •ESLint Migration - Step-by-step migration
- •Biome Config - Full configuration options
- •Type-Aware Rules - Biome 2.0 type inference
- •CI Integration - GitHub Actions setup