React Hooks Patterns

Master modern React hooks patterns for building scalable, maintainable applications with proper state management, side effects, and custom logic reuse.

Common Hooks

useState

const [count, setCount] = useState(0);
const [user, setUser] = useState<User | null>(null);

// Functional updates
setCount(prev => prev + 1);

useEffect

useEffect(() => {
  // Side effect
  const subscription = api.subscribe();
  return () => subscription.unsubscribe();
}, [dependencies]);

useContext

const theme = useContext(ThemeContext);

useMemo & useCallback

const memoized = useMemo(() => expensive(a, b), [a, b]);
const callback = useCallback(() => doSomething(a), [a]);

Custom Hooks

function useFetch<T>(url: string) {
  const [data, setData] = useState<T | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<Error | null>(null);

  useEffect(() => {
    fetch(url)
      .then(res => res.json())
      .then(setData)
      .catch(setError)
      .finally(() => setLoading(false));
  }, [url]);

  return { data, loading, error };
}

Best Practices

1. Always provide dependency arrays
2. Use useCallback for event handlers
3. Create custom hooks for reusable logic
4. Keep components focused and small
5. Use TypeScript for type safety
6. Clean up effects properly
7. Avoid excessive use of useEffect

Resources

• https://react.dev/reference/react
• https://usehooks.com