Designing High-Quality Custom Hooks
A custom hook should hide implementation details while exposing a small, predictable API. For example, useDebouncedValue(value, delay) should not force callers to understand timers, cleanup, or dependency management.
Good hooks separate reusable behavior from UI. A hook may return state, actions, status flags, and refs. Avoid hooks that return a huge object containing every internal detail of a feature.
Custom hooks can compose other hooks. They are a major reason React's function-component model scales beyond simple components.
Debounced value hook
function useDebouncedValue<T>(value: T, delay: number) {
const [debounced, setDebounced] = useState(value);
useEffect(() => {
const id = setTimeout(() => setDebounced(value), delay);
return () => clearTimeout(id);
}, [value, delay]);
return debounced;
}💡 The hook owns the timer lifecycle and exposes only the debounced value.
Key Takeaways
- Custom hooks should expose behavior, not implementation.
- Keep hook APIs small and predictable.
- Hooks can compose state, effects, refs, and other hooks.