typescript

## Components - Use function components with typed props. - Prefer `React.FC` only when children typing is needed; otherwise avoid. - Memoize when beneficial (`React.memo`, `useMemo`, `useCallback`). ## Props & State - Type props with interfaces or type aliases (PascalCase). - Use `readonly` for immutable props/state shapes. - Avoid `any`; use `unknown` when necessary. - Prefer discriminated unions for state machines. ## Hooks - Extract logic into custom hooks. - Type hook return values explicitly. - Avoid unnecessary dependencies in hook arrays. ## Data & Types - Store types in `types.ts` files. - Use Zod for runtime validation. ## Imports & Exports - Prefer named imports and named exports. - Always declare imports at the beginning of source files. - Import order: 1. External libs 2. Internal modules 3. Types - Avoid default exports. ## Error Handling - Use custom error classes with `code` and optional context. - Prefer `Result<T, E>` patterns for recoverable failures. ## Async Patterns - Use `async/await`. - Wrap async code with `try/catch`. - Avoid inline Promises inside JSX. ## Performance - Use `as const` for literals. - Use mapped types for transformations. - Use memoization and stable references to reduce re-renders.