mohan

04-03-2026, 02:43 PM #1

Here are the most commonly asked React questions at Zoho interviews in 2026, based on feedback from recent candidates.

1. What is the Virtual DOM and how does React use it?
The Virtual DOM is a lightweight copy of the actual DOM. React uses a diffing algorithm to compare the previous and current virtual DOM, then updates only the changed parts in the real DOM.

2. Explain the difference between useState and useReducer.
useState is for simple state, useReducer is for complex state logic with multiple sub-values or when next state depends on previous.

3. What are React Server Components?
Components that render on the server and send HTML to the client. They reduce bundle size and improve performance.

4. How does useEffect cleanup work?
The cleanup function runs before the component unmounts and before the effect re-runs.

5. What is React.memo and when should you use it?
A higher-order component that prevents re-renders if props haven't changed. Use for expensive render components.

6. Explain Context API vs Redux.
Context is built-in and good for low-frequency updates. Redux is better for complex global state with middleware support.

7. What are custom hooks?
Reusable functions that extract component logic. They start with 'use' prefix.

8. How do you handle error boundaries?
Class components with componentDidCatch and getDerivedStateFromError methods.

9. What is code splitting in React?
Using React.lazy() and Suspense to load components on demand.

10. Explain the useCallback vs useMemo difference.
useCallback memoizes functions, useMemo memoizes values.

Did you face any of these in your Zoho interview? Share your experience!