What is useCallback and when should it be used?

Short answer: useCallback memoizes a function to avoid unnecessary re-creations. ✅ Syntax: const memoizedCallback = useCallback(() => { doSomething(a, b); }, [a, b]); ✅ Use case: Prevents unnecessary re-renders of child components receiving functions as props. const handleClick = useCallback(() => { console.log("Clicked!"); }, []);

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.