React Js MCQ

React Js MCQ

  • Sharad Jaiswal
  • 20th Nov, 2021

We are introducing here the best React Js MCQ Questions, which are very popular & cover the latest and important topics of React Js. This React Js MCQ Test contains Top 30+ React Js Multiple Choice Questions and Answers, so practice these questions to check your final preparation for React Js Exams, Interviews & Placement Drives.

React Js MCQ Questions

1) What kind of component import React from 'react' is?

  • A. stateless component
  • B.statefull component
  • C.pure component

2) What is ReactJS?

  • A. User-interface framework
  • B.Server-side Framework
  • C.Both server & Client

3) Which of following is used to pass data to a component from outside?

  • A. PropTypes
  • B.setState
  • C.render with arguments
  • D.props

4) What function allows you to render React content in an HTML page?

  • A. React.mount()
  • B.ReactDOM.start()
  • C.ReactDOM.render()
  • D.React.render()

5) React.js was created by

  • A. Jordan Walke
  • B.Jordan mike
  • C.Tim Lee
  • D.Jordan Lee

6) Arbitrary inputs of components in React are called

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

7) What is state in React?

  • A. A persistant storage.
  • B.An internal data store (object) of a component.

8) What does the webpack command do?

  • A. A module bundle
  • B.Runs react local development server.
  • C.Transpiles all the Javascript down into one file
  • D.None of the above

9) What create-react-app command do

  • A. Update a react app
  • B.Creates new react app
  • C.install dependencies

10) How many elements does a react component return?

  • A. 1
  • B.2
  • C.Multiple Elements

11) in which directory react components are saved?

  • A. Inside vendor/
  • B.Inside js/components/
  • C.Inside vendor/components/
  • D.Inside external/components/

12) Everything in react is a ....................

  • A. Class
  • B.Module
  • C.Package
  • D.Component

13) Props are __________ into other components.

  • A. Injected
  • B.Methods

14) React.js Covers only the view layer of the app.

  • A. True
  • B.False

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

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

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

  • A. Action->Dispatcher->View->Store
  • B.Action->Dispatcher->Store->View
  • C.Action->Store->Dispatcher->View
  • D.None of the above

17) How many elements does a react component return?

  • A. 1 Element
  • B.2 Elements
  • C.Multiple Elements
  • D.None of the above

18) ReactJS uses _____ to increase performance.

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

19) For controlled components in react

  • A. Source of truth is DOM
  • B.Source of truth can be anything
  • C.Source of truth is component state
  • D.None of the above

20) What are the two ways that data gets handled in React?

  • A. state & props
  • B.services & components
  • C.None of the above

21) Which of the following option is used to access the state of a component from inside of a member function?

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

22) At the highest level, React components have lifecycle events that fall into

  • A. Destruction
  • B.Initialization
  • C.State/Property Updates
  • D.All of these

23) React is mainly for building ...........

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

24) React supports all the syntax of ........

  • A. ES6
  • B.Redux
  • C.Native Java
  • D.None of the above

25) Which of the following concepts is/are key to ReactJS?

  • A. Event delegation model
  • B.Component-oriented design
  • C.Both of the above
  • D.None of the above

26) What is babel in react?

  • A. Compiler
  • B.Transpiler
  • C.Interpreter
  • D.Both Compiler & Transpiler

27) What is snapshot testing used for in react?

  • A. It allows us to test Javascript objects
  • B.It helps you write applications
  • C.It provides clear, enduring assertions
  • D.None of the above

28) React considers everything as ......................

  • A. Objects
  • B.Elements
  • C.Components
  • D.User interface

29) Javascript is used for dom manipulation in react.

  • A. True
  • B.False

30) In react state can be accessed using ....................

  • A. this.state
  • B.this.state()
  • C.state.current()
  • D.None of the above

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