Biome

Fast, unified linting, formatting, and import organization for JavaScript, TypeScript, JSX, CSS, and GraphQL. Biome 2.4 provides type-aware linting without the TypeScript compiler, GritQL plugins for custom rules, and domain-based rule grouping. Single binary, zero config by default, 97% Prettier compatibility.

Critical Rules

files.ignore DOES NOT EXIST - use files.includes with negation

Biome 2.x only supports files.includes (with an s). There is NO files.ignore, NO files.include (without s), NO files.exclude. Using any of these will throw Found an unknown key errors.

The only valid keys under files are: includes, maxSize, ignoreUnknown. (experimentalScannerIgnores exists but is now marked deprecated in upstream docs and may be removed.)

To exclude files (generated code, vendored files, etc.), use negation patterns in files.includes:

{
  "files": {
    "includes": ["**", "!**/routeTree.gen.ts", "!**/generated/**"]
  }