React Hooks Every Developer Should Know

# React Hooks Every Developer Should Know Hooks let function components use state and lifecycle features that used to require class components. A handful of hooks cover almost everything you'll need day-to-day. ## useState The most common hook — holds a piece of local state and a setter function that triggers a re-render when called. ```jsx const [count, setCount] = useState(0); ``` ## useEffect Runs side effects — data fetching, subscriptions, manual DOM changes — after render. The dependency array controls when it re-runs. ```jsx useEffect(() => { fetchData(); }, [userId]); ``` ## useMemo and useCallback Both exist to avoid unnecessary recalculation or re-creation on every render. `useMemo` memoizes a computed value; `useCallback` memoizes a function reference — useful when passing callbacks to memoized child components. ## useRef Holds a mutable value that doesn't trigger a re-render when changed, commonly used to reference DOM elements directly or store previous values across renders. ## Custom Hooks Once logic is reused across components — like a `useDebounce` or `useFetch` — extracting it into a custom hook keeps components clean and logic testable. ## A Common Mistake Overusing `useMemo`/`useCallback` everywhere adds complexity without real performance benefit. Reach for them only when you've noticed an actual re-render problem, not by default. ## Conclusion Most React apps only ever need these five hooks well understood. Master them deeply before reaching for less common ones like `useReducer` or `useImperativeHandle`.