hooks
useState Hook — Complete Interview Guide
Master useState: snapshot model, functional updates, immutability, batching, lazy init, controlled inputs, and every edge case asked in React interviews.
useCallback Hook — Complete Interview Guide
Learn exactly when useCallback prevents re-renders and when it's wasted overhead — the most misused hook in React.
Custom hook — Complete Interview Guide
Learn React custom hooks with real-world examples like useFetch and useForm.
useMemo Hook — Complete Interview Guide
Learn React useMemo with real examples, performance optimization tips, and differences with useCallback.
useReducer Hook — Complete Interview Guide
Learn useReducer for managing complex state with named transitions — and how it pairs with useContext to replace Redux in mid-sized apps.
useContext Hook — Complete Interview Guide
Master React Context for sharing state across the component tree — and learn the re-render trap that catches every developer.
useRef Hook — Complete Interview Guide
Master useRef for DOM access, mutable values, and breaking stale closures — without triggering re-renders.
useEffect Hook — Complete Interview Guide
Master useEffect: dependency array, cleanup, stale closures, data fetching, race conditions, and every pattern asked in React interviews.
Core
react rendering reconciliation interview questions
What actually happens when state changes — re-renders, virtual DOM, diffing, keys, and the two-phase render model explained precisely.
Fiber Architecture
How React works under the hood — the linked list of work units, double buffering, cooperative scheduling, and why Concurrent Mode was impossible before Fiber.
Concurrent Rendering (18)
What changed in React 18 and why it matters — startTransition, useDeferredValue, automatic batching, flushSync, and the atomic commit guarantee explained precisely.