ReactJs Interview Questions

Introduction To ReactJs Interview Questions And Answers

React is a Javascript library that is used for building user interfaces. It is maintained by Facebook and an individual group of developers. ReactJs is used as a base for a single webpage or mobile application. It deals in the view layer of an application. It is also used for creating reusable UI components. I also help a developer to build a large application in which data can be changed without refreshing it. The main advantage of ReactJs is it is fast, scalable, and simple.

Advantage of ReactJs

Below are the advantages mentioned :

• SEO-friendly: ReactJs is very comfortable with SEO. You can easily run your ReactJs with the servers while other Javascript doesn’t support SEO.
• JSX: In ReactJs for templating we use JSX. JSX is simple JavaScript that allows HTML syntax and other HTML tags in the code. HTML syntax is processed into javascript calls of React framework.
• React Native: It contains a native library that supports Native iOS, Android applications.
• Simplicity: It is very simple to grab. Its component-based approach and well-defined lifecycle are very simple to use.
• Easy to learn: Anyone with a basic knowledge of programming can easily ReactJs. For Learning ReactJs you just need to know the basics of HTML and CSS.
• Data-Binding: ReactJs use one-way data binding and application architecture controls the flow of data via a dispatcher.
• Testability: ReactJs application is very easy to test. Its views are very easy to configure and can be treated as an application.

If you are looking for a job that is related to ReactJs, you need to prepare for the 2021 ReactJs Interview Questions. Though every interview is different and the scope of a job is also different, we can help you out with the top ReactJs Interview Questions with answers, which will help you take the leap and get you success in your interview.

Below are the 10 important 2021 ReactJs Interview Questions and Answers that are frequently asked in an interview. these questions are divided into parts are as follows:

Part 1 –ReactJs Interview Questions (Basic)

This first part covers basic ReactJs Interview Questions and Answers

1. What is React?

Answer:
React is a Javascript Library that is used for building user interfaces. ReactJs is used as a base of a single webpage or mobile application. It deals in the view layer of an application.

2. What is JSX?

Answer:
JSX is simple JavaScript that allows HTML syntax and other HTML tags in the code. HTML syntax is processed into javascript calls of React framework.

Let us move to the next ReactJs Interview Questions

3. What is FLUX in ReactJs?

Answer:
Flux is an application architecture in React view Library which was designed by Facebook for creating data layers in an application based on JavaScript.

4. What do you mean by Props and State in React?

Answer:
This is the basic ReactJs Interview Questions asked in an interview. Props mean the properties of the argument which is passed in the javascript function. A state is used for creating a dynamic and interactive component.

5. What are the refs in React?

Answer:
For focus management, trigger animation we use refs in React. It also contains third-party libraries.

6. What is the difference between ReactJs and AngularJs?

Answer:
Both ReactJs and AngularJs are very powerful and diverse approaches for a front-end web application. It supports all small medium and large enterprise applications. On one side the ReactJs application is SEO friendly, simple, and easy to understand, and on the other side, Angular Js applications are easy to develop and support a different form of testing.

7. How flux is different from Redux?

Answer:
Flux is a container for application state and logic while Redux is a container for javascript apps.

Let us move to the next ReactJs Interview Questions

8. What do you mean a functional component in React?

Answer:
A functional component is those component that returns react elements as an element.

9. What do you mean by reacting routing?

Answer:
In React Routing only a single HTML page will be involved.

10. What is the component of Redux?

Answer:
Action, Reducer, Store, View are the component of Redux.

Part 2 –ReactJs Interview Questions (Advanced)

Let us now have a look at the advanced ReactJs Interview Questions.

11. What are the lifecycle methods of React Components in detail?

Answer:
Some of the most important lifecycles methods are given below:

• componentWillMount()
• componentDidMount()
• componentWillRecieveProps()
• shouldComponentUpdate()
• componentWillUpdate()

12.What are the lifecycle of ReactJs?

Answer:
Initialization, State/Property updates, Destruction are the lifecycle of ReactJs.

Let us move to the next ReactJs Interview Questions

13. What are the advantages of ReactJs?

Answer:

• Application performance will be increased.
• It can be used on both Client and Server side.
• Because of JSX code will become or reliable.
• Testing will become easy.

14. Why we use ReactJs?

Answer:
This is the frequently asked ReactJs Interview Questions in an interview. For handling the view part of the mobile application we use React.

15. Which Company developed React and when the first release got to happen?

Answer:
Facebook is the developer of React and the first release was happen in March 2013.

16. What is the stable version of ReactJs?

Answer:
Version:15.5

17. What is the basic difference between pros and state?

Answer:
The basic difference is: State is mutable and Pros are immutable.

Let us move to the next ReactJs Interview Questions

18. When you will use the class component over a functional component?

Answer:
When your component carrying a state or lifecycle then we will use the Class component.

19. How we share the data between components in React?

Answer:
By using State, Prop we share the data.

Conclusion

If you are preparing for the ReactJs Interview then you should also prepare for the Javascript and you must have practical hands-on. The above article is just covered the basic overview and theoretical knowledge of ReactJs.

Recommended Articles

This has been a guide to the List Of ReactJs Interview Questions and Answers Here we have listed the top 19 Interview Questions and Answers that are 0ften asked in the interview so that candidates can crack the interview easily. You may also look at the following articles to learn more –

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