What is useEffect and when do you use it?

Short answer: useEffect lets you run side effects in functional components (like data fetching, subscriptions, etc.). ✅ Syntax: useEffect(() => { // Side effect return () => { // Cleanup }; }, [dependencies]); ✅ Common use cases: Fetching data Event listeners Updating DOM directly Subscribing to services

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.