React is a frontal-end and open-source JavaScript library which is useful in developing user interfaces especially for applications with a single page. It is useful in building complex and reusable user interface(UI) components of mobile and web applications as it follows the component-based approach.

The Following are constantly asked React interview questions for freshers as well as experienced React developers.

1) What is Reactjs ?

React is a JavaScript library that makes building user interfaces easy. It was developed by Facebook.

2) Does React use HTML?

No, It uses JSX, which is analogous to HTML.

3) When was React first released?

React was first released on March 2013.

4) Give me the two most significant downsides of React

Integrating React with the MVC framework like Rails requires complicated configuration.

React require the users to have knowledge about the integration of the user interface into the MVC framework.

5) What is Flux Concept In React?

Facebook extensively uses flux architecture conception for developing client-side web applications. It is not a frame or a library. It is simply a new kind of armature that complements React and the conception of Unidirectional Data Flow.

6) Delineate the term Redux in React

Redux is a library applied for frontal-end development. It is a state container for JavaScript applications that should be applied for the operation’s state management. You can try and run an application developed with Redux in disparate environments.

7) What is an action in Redux?

It is a function that returns an exploited object. The action type and the exploit data are constantly reposited in the action object. conduct can send data between the Store and the software application. All data retrieved by the Store is produced by the actions.

8) Name The important features of React

Then, are the important features of React.

Allows you to use 3rd party pbraries

Time-Saving

Faster Development

Simppcity and Composable

Fully supported by Facebook

Code Stabipty with One-directional data binding

React Components

9) Explain the term stateless components

Stateless factors are pure functions that render DOM grounded solely on the properties provided to them.

10) Explain React Router

React Router is a routing library that allows you to append new screen flows to your application, and it also keeps the URL in sync with what’s being shown on the runner.

11) What is the popular animation package in React ecosystem?

Popular animation packages in React ecosystem are

React Motion

React Transition Group

12) What is Jest?

Jest is a JavaScript unit testing frame created by Facebook based on Jasmine. It offers automated substitute creation and a jsdom environment. It is so used as a testing component.

13) Name two types of React component

Two types of react Components are:

Function component

Class component

14) Explain synthetic event in React js

A synthetic event is a kind of object which acts as a cross-browser wrapper around the browser’s native event. It so helps us to combine the behaviors of various browsers into signal API.

15) What is React State?

It is an object which decides how a express component renders and how it behaves. The data stores the information which can be changed over the continuance of a React component.

16) How can you update the state by react js?

A state can be streamlined on the component directly or indirectly.

17) Explain the application arrow function in React

The arrow function helps you to prognosticate the behavior of bugs when passed as a callback. Therefore, it prevents bugs caused by this all together.

18) What are the lifecycle steps of React?

Important lifecycle ways of React js are:

Initialization

State/Property updates

Destruction is the lifecycle of React

19) State the difference between React JS and React Native

React JS is a frontal-end open-source JavaScript library used for building UIs.

React Native, is an open-source, mobile framework that allows developers to use React on platforms like Android and iOS.