17/Sep/2021 | 8 minutes to read
Here is a List of essential React JS Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these React JS questions are explained in a simple and easiest way. These basic, advanced and latest React JS questions will help you to clear your next Job interview.
These interview questions are targeted for React developers. You must know the answers of these frequently asked basic and advanced React interview questions to clear an interview. React is becoming more popular and a good choice for developers because of its flexibility and simplicity.
1. What is React?
2. What are the advantages and disadvantages of React JS?
3. How will you differentiate React JS and React Native?
React.js is a
It's just responsible for UI rendering (only View part from MVC Architecture).
ReactNative is a platform to develop cross platform, native mobile applications. It's a framework that comes with many native components and modules to develop high performance mobile applications.
4. What is React Fiber? Differentiate reconciliation and rendering.
React 16 provides a new reconciliation engine known as React fiber which enables incremental rendering of virtual DOM. The Reconciler or reconciliation process just determines which parts of the DOM tree have changed and Renderer updates the rendered app using the inputs from Reconciler. For more visit React Fiber Architecture.
5. Differentiate state and props in React.
ref keyword and its usage in React?
7. Explain dirty checks in React.
8. What is prop drilling? How to avoid it?
9. What is Virtual DOM? How does it work in React?
11. Explain the React DOM. How is it different from React?
12. What is the difference between class component and functional component?
13. Explain Event handling in React.
14. What is the use of
15. What are controlled components in React?
16. Explain Higher Order Components (HOCs). How to create it?
17. What is
18. What is the use of JSX?
19. What is Redux?
20. What is the use of Redux Thunk?
PureComponent is different from
22. Why do we need keys in React?
23. How would you decide between React JS library and Angular framework?
24. Explain the advantages and disadvantages of shallow rendering components in tests?
25. Explain the use of
26. What is the use of
27. How to update state so that it can re-render the component? Or explain
28. Explain ReactJS component lifecycle.
29. What is the use of three dots (...) in React?
30. Explain React Hooks.
31. What are the advantages of Hooks?
32. What is the use of
useState() in React?
34. Differentiate controller vs uncontrolled component.
35. Explain React context.
36. Explain React Fiber.
37. How to add attributes to components conditionally?
38. What is the difference between using constructor vs getInitialState in React JS?
39. How to update a parent's state in React JS?
40. How will you decide to use class based components vs functional components?
41. What is the most common approach to apply styles to react applications?
42. Explain the difference between useCallback and useMemo.
43. What is the use of
componentWillUnmount() method in ReactJS?
44. How does React JS work?
45. Explain React Design Principles.
1. How much will you rate yourself in React JS?
When you attend an interview, Interviewer may ask you to rate yourself in a specific Technology like React JS, So It's depend on your knowledge and work experience in React JS.
2. What challenges did you face while working on React JS?
This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to React JS in your Project.
3. What was your role in the last Project related to React JS?
It's based on your role and responsibilities assigned to you and what functionality you implemented using React JS in your project. This question is generally asked in every interview.
4. How much experience do you have in React JS?
Here you can tell about your overall work experience on React JS.
5. Have you done any React JS Certification or Training?
It depends on the candidate whether you have done any React JS training or certification. Certifications or training are not essential but good to have.
We have covered some frequently asked React JS Interview Questions and Answers to help you for your Interview. All these Essential React JS Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any React JS Interview if you face any difficulty to answer any question please write to us at firstname.lastname@example.org. Our IT Expert team will find the best answer and will update on the portal. In case we find any new React JS questions, we will update the same here.