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ReactJS Quiz Set - 4
Question 1
React is mainly used for building ___.
- A
Database
- B
Connectivity
- C
User interface
- D
Design Platform
Question 2
The lifecycle methods are mainly used for ___.
- A
keeping track of event history
- B
enhancing components
- C
freeing up resources
- D
none of the above
Question 3
___ can be done while multiple elements need to be returned from a component
- A
Abstraction
- B
Packing
- C
Insulation
- D
Wrapping
Question 4
Which is the right way of accessing a function fetch() from an h1 element in JSX?
- A
<h1>{fetch()}</h1>
- B
<h1>${fetch()}</h1>
- C
<h1>{fetch}</h1>
- D
<h1>${fetch}</h1>
Question 5
Which of the following methods in a React Component should be overridden to stop the component from updating?
- A
willComponentUpdate
- B
shouldComponentUpdate
- C
componentDidUpdate
- D
componentDidMount
Question 6
What is used to pass data to a component from outside?
- A
setState
- B
render with arguments
- C
PropTypes
- D
props
Question 7
Which of the following methods in a React Component is called after the component is rendered for the first time?
- A
componentDidUpdate
- B
componentDidMount
- C
componentMounted
- D
componentUpdated
Question 8
Which of the following is the correct syntax for a button click event handler foo?
- A
<button onclick={this.foo()}>
- B
<button onclick={this.foo}>
- C
<button onClick={this.foo()}>
- D
<button onClick={this.foo}>
Question 9
What will happen if you call setState() inside render() method?
- A
Repetitive output appears on the screen
- B
Duplicate key error
- C
Stack overflow error - D
Nothing happens
Question 10
What will happen if the following render() method executes?
render(){
let langs = ["Ruby","ES6","Scala"]
return <div>{langs.map(it => <p>{it}</p>)}</div>
}
- A
Displays the list of languages in the array
- B
Error. Cannot use direct JavaScript code in JSX
- C
Displays nothing
- D
Error. Should be replaced with a for..loop for correct output
There are 15 questions to complete.
