Top 50 React JS Interview Questions.

Q1: What is React?

Ans. React is a front-end JavaScript library that mainly follows the component-based approach for building a user interface (UI) components for a single page application. It is also used for handling the view layer in both mobile and web apps. Moreover, react plays a crucial role in developing interactive mobile and web UIs. It was created and developed by Jordan Walke; it was deployed first on the Facebook newsfeed in 2011.

Q2: Why React is used?

Ans: The following reasons make one to use React for building User Interfaces (UI), and they are:

Easy to learn nature
Simplicity
High scalability
Increase performance
Also Read: Full Stack Developer Interview Questions

Q3: How React works?

Ans. Below is the sequence of steps which gives an idea about how does react work

Firstly the react runs the diffing algorithm to identify the changes that are made in the virtual DOM.
Next step is reconciliation, this is used to update the DOM as per the new features.
Now, the virtual DOM, which is lightweight in nature and is detached from the specific implementation of the browser.
Followingly the ReactElements which are present in virtual DOM are used to build basic nodes.
Finally, if the ReactComponent changes the state; the diffing algorithm runs faster and identify the changes. After identification, it automatically updates the DOM with the change difference.
Q4: What are the features of ReactJS?

Ans: The features of React JS are as follows:

1. React improves SEO performance
   React boost the performance of the SEO to higher levels as a search engine faces the problem while reading JavaScript of high loaded applications.

2. React acts as a standard for mobile app development
   It provides a transition process as an ideal solution for both mobile and web applications for building rich user interfaces.

3. React makes the process of writing components easier
   Using React along with JSX will make you write components and code efficiently and clearly.

4. React increases efficiency
   As the React boost the efficiency of components by reusing them. This is the reason why it is considered as an ideal feature of React. It is considered as the most reusable system component.

5. React ensures stable code

It ensures the stability of the code of an application by making use of downward dataflow.

For more information vist :Mindmajix React Interview Questions.

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