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React, also known as React.js or ReactJS, is a front-end, open-source JavaScript library used to create user interfaces through the use of UI components. If you are a Java programmer, you can expect advanced ReactJS interview questions in your front-end engineer interview.
To understand your experience with various Java tools and frameworks, FAANG+ companies typically test your knowledge of Java application tools and Microservices, including ReactJS. To ace your technical interview, it is critical to know the answers to frequently asked advanced ReactJS interview questions.
In this article, we will present the commonly asked and popular advanced ReactJS interview questions and answers. We also present some sample questions that you can practice answering to ace the actual interview.
Popular Advanced ReactJS Interview Questions and Answers
Q1. What are Some Key Benefits of Using ReactJS?
This is a common advanced ReactJS interview question asked in technical interviews. Some key benefits of using ReactJS include:
- ReactJS is the best framework for front-end development in Java as it is packed with a host of features.
- ReactJS uses a Virtual DOM, thereby enhancing the performance of applications built using the framework.
- React employs a component-based architecture and allows components to be reused with great ease.
- React has a vast list of tools and libraries, providing impressive depth and flexibility.
Q2. What is the Virtual DOM in React?
Virtual DOM is a feature through which a virtual version of the real DOM is placed in the memory. Using the ReactDOM library, the virtual and real DOMs are synced whenever required.
Q3. What are the Different Lifecycle Phases in ReactJS?
This is another important advanced ReactJS interview question asked in technical interviews. Components in ReactJS fundamentally go through three lifecycle phases.
- Unmounting
- Mounting
- Updating
Q4. What are the Various Lifecycle Methods in the Mounting Lifecycle Phase?
The various methods in the mounting lifecycle phase include:
- Render
- ComponentWillMount
- ComponentDidMount
Q5. What are the Different Lifecycle Methods in the Updating Phase?
You can answer this advanced ReactJS interview question by stating that the lifecycle methods in the updating phase include:
- ComponentWillReceiveProps
- Render
- ComponentDidUpdate
- ShouldComponentUpdate
- ComponentWillUpdate
Q6. What is an Event in ReactJS?
Events are actions that are performed by the user or computer. Actions such as clicking and pressing keys are examples of Events in ReactJS. Unlike in HTML, where events are in lowercase, events in React are in CamelCase.
Q7. What are Some Prime Features of the ReactJS Framework?
This again is a frequently asked ReactJS interview question in technical interviews.
The prime features of the ReactJS framework include:
- ReactJs allows for Data Binding, where developers can choose what elements users can access and what elements are hidden. The security of applications created is also foolproof because of this feature.
- ReactJS has a unidirectional data flow.
- ReactJs employs Virtual DOM instead of RealDOM.
- React mainly uses Server-side rendering.
Q8. What is Redux?
This is another popular advanced ReactJS interview question. Redux is a popularly used library for front-end development. It is loaded with a spate of features that help accomplish advanced front-end tasks using UI components. Applications built using Redux are easy to test and can seamlessly run on multiple framework environments.
Q9. What are some advantages of using Flux?
Flux offers a bunch of advantages, the most important ones being:
- It ensures uniformity of code execution, thereby preventing Runtime errors.
- It helps to perform updates more effectively through unidirectional data flow, thereby improving the efficiency of the application.
Q10. What are some functions that can be performed using HOC?
Using HOC, you can -
- Render Hijacking
- Manipulate and Reuse code
- Manipulate Props
Sample Advanced ReactJS Interview Questions for Practice
In this section, we’ll look at some additional ReactJS interview questions that you can practice for your upcoming interview.
11. Why do we use Keys in ReactJS lists?
12. How can the transversal of lists be achieved in ReactJS?
13. What do you understand about components in React?
14. Explain the two types of Components in ReactJS?
15. What are Synthetic events in React?
16. What are Pure Components in ReactJS?
17. What are some important features of Redux?
18. What do you understand about Flux in React?
19. Why are Routers used in ReactJS?
20. What are some disadvantages associated with the ReactJS framework?
21. Why can’t browsers read JSX? How can browsers be made to read JSX?
22. What do you understand about Higher-Order Components in ReactJS?
23. What do you understand by References in ReactJS?
24. What are Props in ReactJS?
25. How do you modularize code in the ReactJS framework?
26. What is the use of Webpack in React?
27. What is Babel in ReactJS?
28. What is Prop-drilling in ReactJS?
29. What are Error boundaries in ReactJS?
30. What do you understand about the Strict mode in React?
These above advanced ReactJS interview questions will help you understand the type of questions asked in your Java developer interview, especially if you are a front-end developer.
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FAQs on Advanced ReactJS Interview Questions
1. Why Should I Focus on Advanced ReactJS Questions for My Interview?
Advanced ReactJS questions help interviewers assess your deep understanding of the framework, your ability to solve complex problems, and your readiness to handle challenging tasks in a professional environment. This is especially important for roles at top-tier tech companies.
2. How can I Best Prepare for Advanced ReactJS Interview Questions?
Focus on understanding the core concepts and advanced features of ReactJS, such as lifecycle methods, Virtual DOM, state management, and hooks. Practice coding problems, build small projects, and review common interview questions to solidify your knowledge.
3. What is the Importance of Understanding the Virtual DOM in ReactJS?
The Virtual DOM is crucial for ReactJS performance optimization. It allows React to efficiently update and render components by minimizing direct manipulations of the real DOM. A deep understanding of the Virtual DOM can help you write more efficient and performant React applications.
4. How do Lifecycle Methods Affect the Performance of a React Application?
Lifecycle methods allow you to hook into different phases of a component's life (mounting, updating, and unmounting) to perform operations like data fetching, resource cleanup, or DOM manipulation. Proper use of these methods can significantly impact the performance and behavior of your application.
5. Why is State Management Important in React Applications?
State management is crucial for handling the dynamic data in your application. Proper state management ensures that your application behaves predictably, is easier to debug, and can scale effectively. Libraries like Redux or Context API are often used for managing state in larger applications.
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