react js interview questions

TOp MOst (FAQ) “React JS” Interview Questions with Answers(2021)

ReactJS Interview Questions & Answers….Coding exercise Interview Questions with Answers. Frequently asked: React JS Interview Questions and Answers . Top React Interview Questions which an aspiring front end developer must prepare. … Type, Open Source MVC Framework, Open Source JS Framework. js developer with Total. Submit an Interview Question. React Interview Questions and Answers You Should Know ·

Basic & Advanced ReactJS Interview Questions and Answers

Q1.What is the ReactJS cover?

A. Data layer in an application)
B. User Interface layer in an application
C. Both A & B
D. All are Correct

Option B – user interface layer in an application

Q2.What is the ReactJS use to increase performance?

A. Virtual DOM
B. Original DOM
C. Local DOM
D. None of the Above

Option A – virtual Dom

Q3.A valid react component can return …… number of elements. find out?

A. 1
B. 2
C. 3
D. None of the Above

Option A – 1

Q4.For controlled components in react Choose Below one?

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

Option B – source of truth is compliment state

Q5. What is React is a __

A. Javascript library
B. Javascript framework
C. Both of above
D. None of above

Option A – Javascript library

Q6.Which of the accompanying API is a MUST for every ReactJS component?

A. getInitialState
B. render
C. renderComponent
D. None

Option C – render component

Q7.Find out you access the state of a component from inside of a member function?

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

Option D – this.values

Q8.Which of these a good use case for using a function while rendering a dynamic list of items

A. If we need to compute a value based on properties of items in the loop.
B. None. Functions should not be used while rendering a dynamic list.
C. To make the code shorter

Option A – If we need to compute a value based on properties of items in the loop.

Q9.What is compute a value based on properties of items in the loop.

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

Option A – virtual Dom

Q10.Which of the default port for webpack dev server?

A. 3000
B. 8080
C. 3306
D. 8809

Option B – 8080

Q11. Who developed by React Js
B. Microsoft
C. Facebook
D. None of above

Option C – facebook

Q12.In relation to React js component lifecycle, Find out the statement is true

A. only function component can have life cycle
B. Only class components can have life cycle
C. Both type of components can have life cycle
D. None of above

Option B – Only class components can have life cycle

Q13.In respond, this is utilized to pass information to part from outside?

A. set state
B. render with argument
C. props
D. propTypes

Option C – props

Q14.which of these react is __

A. module
B. component
C. package
D. class

Option B – component

Q15.Find out the following is a correct definition of state in react?

A. A persistent storage
B. An internal data store (object) of component
C. Both
D. None

Option B – An internal data store (object) of component

Q16.Regarding React js components, Find out the Following statement is true?

A. function components can have state
B. function components are light weight
C. class components are light weight
D. class components are faster than function component

Option B – function components are light weight

Q17.What will occur in the event that you render an info component with Disabled = {false}

A. It will be rendered as enabled
B. It will be rendered as disabled
C. It will not be rendered at all

Option A – It will be rendered as enabled

Q18.Find out the command is used Install create-react-app?

A. npm install -g create-react-app
B. npm install create-react-app
C. npm install -f create-react-app
D. install -g create-react-app

Option A – npm install -g create-react-app

Q19.Initial Release to the Public (V0.3.0) Find out the?

A. 2011
B. 2012
C. 2013
D. 2014

Option c – 2013

Q20.A class is a type of function, but instead of using the keyword function to initiate it, Find out the keyword?

A. constructor
B. class
C. object
D. dataObject

Option B – class

Q21.To create a class inheritance, use the __ keyword. Fill the Blank?

A. create
B. inherits
C. extends
D. this

Option C – extends

Q22.In ES6, what number of methods of characterizing your factors?

A. 3
B. 4
C. 5
D. 6

Option A – 3

Q23.What Does React creates a VIRTUAL DOM in memory.

A. TRUE
B. FALSE
C. Can be true or false
D. Can not say

Option A – true

Q24.In React, component properties should be kept in an object called?

A. component
B. super
C. state
D. props

Option C – state

Q25.Find out react is a?

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

Option D- component

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