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Yogesh Chavan
Yogesh Chavan

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100+ React.js And Next.js Interview Questions With Answers

Are you gearing up for a React.js/Next.js interview and want to stand out from the crowd? Whether you're a fresher aiming for your first role or an experienced developer seeking to sharpen your expertise, mastering React.js/Next.js is essential to your success in today's tech landscape.

This comprehensive guide covers 100+ React.js + Next.js interview questions — each paired with detailed answers and practical insights — designed to help you confidently tackle any interview scenario.

Dive in to discover everything from fundamental concepts to advanced patterns, and equip yourself with the real-world knowledge you need to impress employers and accelerate your career in modern web development.


React.js Questions

1. What is useRef and when would you use it?

What is useRef

2. Explain code splitting and lazy loading in React

Code Splitting

3. What will happen in this code?

4. What causes unnecessary re-renders and how do you prevent them?

Extra Rerender

5. What is Reconciliation in React?

Reconciliation

6. What is React Fiber?

React Fiber

7. What is forwardRef?

forwardRef

8. What are Fragments and why use them?

Fragments

9. What is the Container/Presentational pattern?

Container pattern

10. What are some React best practices?

Best Practices

11. What is a race condition and how do you prevent it?

Race Condition

12. What is useReducer hook and when should you use it?

useReducer

13. How do you type hooks with TypeScript?

TypeScript With Hooks

14. What's wrong with this code?

What's Wrong

15. Why does this component render infinitely?

Rerender


Next.js Questions

1. What's the difference between searchParams and params in page props?

Params

2. What's wrong with this environment variable usage?

Environment Variable

3. Why doesn't this cookie update work?

4. Why does this cause request timeout?

Timeout

5. What's wrong with this Link prefetch behavior?

Link Prefetch

6. What's the purpose of the Image component’s priority prop?

Image Component

7. What's wrong with this Server Action?

Server Action

8. What's the difference between next build and next build --profile?

Next Build

9. Why does this component cause a hydration error?

Hydration Error

10. What happens when you export this config?

Export Config

11. How do you handle errors in the app directory?

Errors In App Directory

12. What's the issue with this Server Action form?

Sevrer Action Form

13. Why doesn’t this middleware redirect work?

Middleware Redirect

14. What's the purpose of generateStaticParams?

generateStaticParams

15. How do you implement Incremental Static Regeneration (ISR) in Next.js 13+?

ISR

These were just a few sample questions and answers from the Next.js + React.js Interview Questions eBook.

Download them as a PDF and access all 100+ questions.

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