This skill guides you through migrating a JavaScript/TypeScript project from Prettier or Biome to Oxfmt . Overview Oxfmt is a high-performance, Prettier-compatible code formatter. Most Prettier options are supported directly. An automated migration tool is built into oxfmt, supporting both Prettier and Biome as migration sources. Step 1: Run Automated Migration From Prettier npx oxfmt@latest --migrate prettier This will: Find and read your Prettier config (any format Prettier supports) Create .oxfmtrc.json with migrated options Migrate .prettierignore patterns to ignorePatterns Migrate prettier-plugin-tailwindcss options to sortTailwindcss Detect prettier-plugin-packagejson and enable sortPackageJson From Biome npx oxfmt@latest --migrate biome This will: Find and read biome.json or biome.jsonc Create .oxfmtrc.json with migrated options Migrate negated patterns from files.includes to ignorePatterns Map Biome's two-level config ( formatter. and javascript.formatter. ) to oxfmt options Biome option mapping: Biome oxfmt formatter.indentStyle ( "tab" / "space" ) useTabs ( true / false ) formatter.indentWidth tabWidth formatter.lineWidth printWidth javascript.formatter.quoteStyle singleQuote javascript.formatter.jsxQuoteStyle jsxSingleQuote javascript.formatter.quoteProperties ( "asNeeded" ) quoteProps ( "as-needed" ) javascript.formatter.trailingCommas trailingComma javascript.formatter.semicolons ( "always" / "asNeeded" ) semi ( true / false ) javascript.formatter.arrowParentheses ( "asNeeded" ) arrowParens ( "avoid" ) formatter.bracketSameLine bracketSameLine formatter.bracketSpacing bracketSpacing formatter.attributePosition ( "multiline" ) singleAttributePerLine ( true ) Notes (both sources): Fails if .oxfmtrc.json already exists. Delete it first if you want to re-run. If no source config is found, creates a blank .oxfmtrc.json instead. overrides cannot be auto-migrated for either source and must be converted manually. Step 2: Review Generated Config After migration, review the generated .oxfmtrc.json for these key differences: printWidth Prettier and Biome default is 80, oxfmt default is 100. The migration tool sets printWidth: 80 if not specified in your source config. Decide whether to keep 80 or adopt 100. Unsupported Options (Prettier only) These Prettier options are skipped during migration: Option Status endOfLine: "auto" Not supported. Use "lf" or "crlf" explicitly experimentalTernaries Not supported in JS/TS files yet experimentalOperatorPosition Not supported in JS/TS files yet sortPackageJson (Prettier only) Enabled by default in oxfmt, but the migration tool disables it unless prettier-plugin-packagejson was detected. Review whether you want this enabled. Note: Oxfmt's sorting algorithm differs from prettier-plugin-packagejson . embeddedLanguageFormatting (Prettier only) Embedded language formatting (e.g., CSS-in-JS) generally works, but some formatting may differ from Prettier. overrides The overrides field cannot be auto-migrated from either Prettier or Biome. Convert manually: { "overrides" : [ { "files" : [ ".md" ] , "options" : { "tabWidth" : 4 } } ] } Nested Config Oxfmt does not support nested configuration files (e.g., a separate .oxfmtrc.json in a subdirectory). If your project used per-directory Prettier or Biome configs, consolidate them using overrides with file glob patterns, or run oxfmt separately per directory with different working directories. Prettier-Compatible Options These options transfer directly with the same behavior: tabWidth , useTabs , semi , singleQuote , jsxSingleQuote , quoteProps , trailingComma , arrowParens , bracketSpacing , bracketSameLine , endOfLine , proseWrap , htmlWhitespaceSensitivity , singleAttributePerLine , vueIndentScriptAndStyle Step 3: Configure Oxfmt Extensions Oxfmt offers features not available in Prettier: sortImports Sort import statements, inspired by eslint-plugin-perfectionist/sort-imports (disabled by default): { "sortImports" : { "partitionByNewline" : true , "newlinesBetween" : false } } sortTailwindcss Replaces prettier-plugin-tailwindcss . Auto-migrated with renamed options: Prettier (top-level) oxfmt ( sortTailwindcss. ) tailwindConfig config tailwindStylesheet stylesheet tailwindFunctions functions tailwindAttributes attributes tailwindPreserveWhitespace preserveWhitespace tailwindPreserveDuplicates preserveDuplicates Other Extensions Option Default Description insertFinalNewline true Whether to add a final newline at end of file sortPackageJson true Sort package.json keys. Set { "sortScripts": true } to also sort scripts Step 4: Update CI and Scripts Replace formatter commands with oxfmt:

Before (Prettier)

npx prettier --write . npx prettier --check .

Before (Biome)

npx biome format --write . npx biome check .

After

npx oxfmt@latest npx oxfmt@latest --check Common CLI Options Prettier / Biome oxfmt prettier --write . / biome format --write . oxfmt (default: cwd, --write mode) prettier --check . / biome check . oxfmt --check prettier --list-different . oxfmt --list-different prettier --config path oxfmt --config path prettier --ignore-path .prettierignore oxfmt --ignore-path .prettierignore cat file | prettier --stdin-filepath=file.ts cat file | oxfmt --stdin-filepath=file.ts File Type Coverage JS/TS: Formatted natively by oxfmt TOML: Formatted natively (via taplo) CSS, HTML, YAML, Markdown, GraphQL, etc.: Delegated to Prettier internally (when using npx oxfmt ) Tips EditorConfig: Oxfmt reads .editorconfig automatically for useTabs , tabWidth , endOfLine , insertFinalNewline , and printWidth . Options in .oxfmtrc.json take precedence. CI: Use npx oxfmt@latest --check to enforce formatting in CI. LSP: Run oxfmt --lsp for editor integration via Language Server Protocol. Schema support: Add "$schema": "./node_modules/oxfmt/configuration_schema.json" to .oxfmtrc.json for editor autocompletion. Init: Run npx oxfmt@latest --init to create a default .oxfmtrc.json without migration. References CLI Reference Config File Reference Unsupported Features