biome-to-oxc

name: biome-to-oxc description: Migrate JavaScript/TypeScript projects from Biome to oxlint + oxfmt with Prettier fallback. Use when user asks to "migrate to oxlint", "switch from biome to oxc", "use oxfmt", or wants to adopt the oxc toolchain for linting and formatting.

Biome to Oxc Migration

Migrate from Biome to oxlint (linting) + oxfmt (formatting) with Prettier for unsupported file types.

File Type Strategy

Migration Checklist

1. Remove Biome packages - @biomejs/biome, ultracite, or similar presets
2. Add new packages - oxlint, oxfmt, prettier, framework-specific prettier plugins if needed
3. Delete biome.json or biome.jsonc
4. Create .oxlintrc.json
5. Create .prettierrc.json and .prettierignore
6. Update build scripts - Replace biome commands with oxlint/oxfmt/prettier
7. Update VSCode settings - Switch formatter to oxc.oxc-vscode
8. Run format and lint - Verify everything works

Configuration Templates

.oxlintrc.json

{
  "$schema": "./node_modules/oxlint/configuration_schema.json",
  "plugins": ["typescript", "import", "unicorn", "oxc", "jsdoc", "promise", "node"],
  "rules": {}
}

Available plugins: eslint, react, unicorn, typescript, oxc, import, jsdoc, jest, vitest, jsx-a11y, nextjs, react-perf, promise, node, vue

Enable plugins relevant to your project. For library projects, exclude framework-specific plugins (react, vue, nextjs, jest, vitest).

.prettierrc.json

{
  "printWidth": 120,
  "plugins": ["prettier-plugin-astro"]
}

Add plugins as needed: prettier-plugin-astro, prettier-plugin-svelte, prettier-plugin-tailwindcss

.prettierignore

dist/
node_modules/
**/*.ts
**/*.tsx
**/*.js
**/*.jsx
**/*.json
**/*.css

Exclude files handled by oxfmt.

VSCode Settings

{
  "editor.defaultFormatter": "esbenp.prettier-vscode",
  "[javascript][typescript][javascriptreact][typescriptreact][json][jsonc][css]": {
    "editor.defaultFormatter": "oxc.oxc-vscode"
  },
  "editor.codeActionsOnSave": {
    "source.fixAll.oxc": "always"
  }
}

Rule Migration

Common Biome to oxlint rule mappings:

oxlint uses ESLint-compatible rule names with kebab-case.

CLI Commands

# Lint with auto-fix
oxlint --fix

# Format with oxfmt (use .gitignore for ignoring)
oxfmt --write --ignore-path=.gitignore .

# Format remaining files with Prettier
prettier --write --no-error-on-unmatched-pattern "**/*.{md,mdx,astro,yaml,yml}"

Note: oxfmt reads .prettierignore by default. Use --ignore-path=.gitignore to use gitignore instead.