Reactjs MCQ questions and answers with PDF. Helpful for online test, quiz, interview and competitive exams. These are the most asked and most important MCQs for students. In this post we write only 20 Question but no worry you can download PDF where you see all questions.
ReactJS MCQ Questions
1. Which of the following is used in Readt.js to increase performance?
a) Virtual DOM
b) Original DOM
c) Both A and B
d) None of the above
Ans. A
2. What is ReadtJS?
a) Server-side framework
b) user interface framework
c) both a and b
d) none of the above
Ans. B
3. Identify the one which is used to pass data to components from outside
a) Render with arguments
b) setState
c) PropTypes
d) props
Ans. D
4. Who created React.Js?
a) Jordan Mike
b) Jordan Walke
c) Tim Lee
d) Jordan Lee
Ans. B
5. In Which language is React.js written?
a) Python
b) JavaScript
c) Java
d) PHP
Ans. B
6. What is Babel?
a) JavaScript compiler
b) JavaScript interpreter
c) JavaScript transpiler
d) None of these
Ans. A
7. Identify the command used to create a react app.
a) npm install create-react-app
b) npm install –g create-react-app
c) install –g create-react-app
d) none of the above
Ans. B
8. Which of the following port is the default where webpack-dev-server runs?
a) 3000
b) 3306
c) 3030
d) 8080
Ans. D
9. How many elements can a valid react component return?
a) 1
b) 2
c) 3
d) 4
Ans. A
10. A state in React.js is also known as?
a) The internal storage of the component
b) External storage of the component
c) Permanent storage
d) All of the above
Ans. A
11. Which of the following method is used to access the state of a component from inside of a member function?
a) this.prototype.stateValue
b) this,getState()
c) this.values
d) this.state
Ans. C
12. What are arbitary inputs of components in react also known as?
a) Elements
b) Props
c) Keys
d) Ref
Ans. B
13. In MVC, what does React.js act as?
a) Model
b) Controller
c) Router
d) Middleware
Ans. B
14. Among the following options, choose the one which helps react for keeping their data uni-directional?
a) DOM
b) Flux
c) JSX
d) Props
Ans. B
15. Using which of the following command can prevent default behaviour at in react?
a) preventDefault()
b) avoidDefault()
c) revokeDefault()
d) None of the above
Ans. A
16. Identify the smallest building block of React.JS
a) Props
b) Elements
c) Components
d) None of the above
Ans. C
17. What is React.JS mainly used for building?
a) Database
b) Connectivity
c) User interface
d) Design interface
Ans. C
18. Which of the following function is used to change the state of react component?
a) this.setState()
b) this.state()
c) this.setChangeState()
d) None of the above
Ans. A
19. Among the following which acts as the input of class-based component?
a) Factory
b) Render
c) Class
d) props
Ans. D
20. Among the following which is used to create a class inheritance?
a) Inherits
b) Extends
c) Create
d) this
Ans. B
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