languageGuide for core TypeScript language features and the type system. Use when writing or reviewing TypeScript types, enabling strict mode, choosing a utility type, designing generics or conditional types, writing declaration files, or modeling data with discriminated unions.
lintingGuide for linting and formatting TypeScript with ESLint, typescript-eslint, Biome, and Prettier. Use when configuring flat-config ESLint, choosing typescript-eslint's strict or recommended presets, evaluating Biome as an ESLint/Prettier replacement, wiring pre-commit lint hooks, or adding lint/forma
nodeGuide for the Node.js runtime in TypeScript projects. Use when working with async/await and Promises, reading or writing streams, choosing between ESM and CommonJS, configuring package.json exports, picking npm/pnpm/bun, managing Node versions with mise, or wiring Node CI/CD.
testingGuide for testing TypeScript projects with Vitest, Jest, and Playwright. Use when writing unit tests, mocking modules or timers, asserting types at compile time, running end-to-end browser tests, configuring coverage thresholds, or wiring test tasks into CI.