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TypeScript Policy

Guardrails​

  • TypeScript everywhere (apps & packages)
  • strict mode ON (noImplicitAny, exactOptionalPropertyTypes, ...)
  • ESM‑first modules
  • Path aliases + Project References
  • No decorators

Base tsconfig excerpt:

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ESNext",
    "moduleResolution": "Bundler",
    "strict": true,
    "jsx": "react-jsx",
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "baseUrl": ".",
    "paths": { "@repo/*": ["packages/*/src"], "@ui/*": ["packages/ui/src/*"] }
  },
  "include": ["apps", "packages"]
}

Library build tool: tsup:

{ "type": "module", "main": "dist/index.js", "types": "dist/index.d.ts", "scripts": { "build": "tsup src/index.ts --dts --format esm,cjs" } }

LLM Notes​

  • Output ESM unless a dependency requires CJS; for dual-builds, ship both.
  • Respect path aliases. Import from @repo/* rather than deep relative paths.