react-dev

Topics in the source

• React TypeScript

Type-safe React = compile-time guarantees = confident refactoring. Building typed React components Implementing generic components Typing event handlers, forms, refs Using React 19 features (Actions, Server Components, use()) Router integration (TanStack Router, React Router) Custom hooks with proper typing NOT for: non-React TypeScript, vanilla JS React React 19 breaking changes require migration. Key patterns: ref as prop - forwardRef deprecated: useActionState - replaces useFormState: use() - unwraps promises/context: See react-19-patterns.md for useOptimistic, useTransition, migration checklist. Props - extend native elements: Children typing: Discriminated unions for variant props: Use specific event types for accurate target typing: See event-handlers.md for focus, drag, clipboard, touch, wheel events. useState - explicit for unions/null: useRef - null for DOM, value for mutable: useReducer - discriminated unions for actions: Custom hooks - tuple returns with as const: useContext - null guard pattern: See hooks.md for useCallback, useMemo, useImperativeHandle, useSyncExternalStore. Generic components infer types from props - no manual annotations at call site. Pattern - keyof

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