17th
Mar
React JS MCQ

React JS MCQ

  • Admin
  • 17th Mar, 2023
  • 443 Followers

React JS is the latest and most popular JavaScript framework. This React Js MCQ Test contains 30+ React Js Multiple Choice Questions. So, you have to select the right answer to check your final preparation for your Exams & Interviews. Besides this, you can also download the PDF Completely Free.

React Js MCQ Online Test

1) React.js is a free and open-source front-end .................

  • A. JavaScript library
  • B.Bootstrap library
  • C.CSS library
  • D.None of the Above

2) React.js was Initially released in ................

  • A. May 29, 2013
  • B.April 29, 2013
  • C.June 29, 2013
  • D.May 29, 2014

3) React.js has Written in ................

  • A. JavaScript
  • B.Python
  • C.Java
  • D.Php

4) ............. is used in React.js to increase performance?

  • A. Virtual DOM
  • B.Original DOM
  • C.Both Original & Virtual DOM
  • D.None of the Above

5) What is Babel?

  • A. A JavaScript transpiler
  • B.A JavaScript interpreter
  • C.A JavaScript Compiler
  • D.None of the above
Download Free : React JS MCQ PDF

6) Which of the following command is used to create a react app?

  • A. install -g create-react-app
  • B.npm install create-react-app
  • C.npx create-react-app reactapp
  • D.None of the Above

7) .............. port is the default where the webpack-dev-server will run.

  • A. 3030
  • B.8080
  • C.3306
  • D.3000

8) A valid react component can return only ......... element.

  • A. 2
  • B.3
  • C.1
  • D.4

9) A state in React.js is also known is ..............

  • A. A permanent storage.
  • B.An Internal storage of the component.
  • C.An External storage of the component.
  • D.All of the above

10) In React js what is used to pass data to a component from outside?

  • A. setState
  • B.render with arguments
  • C.props
  • D.PropTypes
Read Best: React Js Interview Questions

11) How can you access the state of a component from inside of a member function?

  • A. this.getState()
  • B.this.values
  • C.this.prototype.stateValue
  • D.this.state

12) Props are __________ into other components.

  • A. Methods
  • B.Injected
  • C.Both 1 & 2
  • D.All of the above

13) What is a react.js in MVC?

  • A. Middleware
  • B.Controller
  • C.Model
  • D.View

14) Keys are given to a list of elements in react. These keys should be -

  • A. Do not requires to be unique
  • B.Unique in the DOM
  • C.Unique among the siblings only
  • D.All of the above

15) Which of the following is the correct data flow sequence of flux concept?

  • A. Dispatcher->Action->Store->View
  • B.Action->Dispatcher->View->Store
  • C.Action->Dispatcher->Store->View
  • D.Action->Store->Dispatcher->View
Download Free: React Js Interview Questions PDF

16) React.js covers only the view layer of the app.

  • A. Yes
  • B.No

17) React was originally developed by ...............

  • A. Jordan Walke
  • B.Rasmus Lerdorf
  • C.Miško Hevery
  • D.None of the above

18) .............. helps react for keeping their data unidirectional.

  • A. JSX
  • B.Flux
  • C.Dom
  • D.Props

19) React merges the object you provide into the current state using setState().

  • A. True
  • B.False

20) Arbitrary inputs of components are called ...........

  • A. Ref
  • B.Keys
  • C.Props
  • D.Elements

21) We can prevent default behavior in React using ............

  • A. revokeDefault()
  • B.preventDefault()
  • C.avoidDefault()
  • D.None of the Above

22) React is mainly used for building ................

  • A. Database
  • B.User interface
  • C.Connectivity
  • D.Design platform

23) What is the smallest building block of ReactJS?

  • A. props
  • B.elements
  • C.components
  • D.None of the Above

24) Which function is used to change the state of react component?

  • A. this.State{}
  • B.this.setState
  • C.this.setChangeState
  • D.None of the Above

25) What is React js?

  • A. client-side framework
  • B.server-side framework
  • C.ui (user interface) framework
  • D.None of the above

26) Which of the following is used to create a class inheritance?

  • A. this
  • B.Create
  • C.Extends
  • D.Inherits

27) What are the ways to handle data in react.js?

  • A. state & services
  • B.state & component
  • C.State & props
  • D.services & component

28) Which of the following method is used for the parent class in React.Js?

  • A. self()
  • B.this()
  • C.Inherits()
  • D.super()

29) React components are saved in ....................... directory.

  • A. js/components
  • B.components/js
  • C.vendor/components
  • D.None of the above

30) useLayoutEffect function is used to .................

  • A. complete the update
  • B.optimize for all devices
  • C.change the layout of the screen
  • D.when we need the browser to paint before effectors

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