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React Basics
1/25
The lifecycle methods are mainly used for ___.
keeping track of event history
enhancing components
freeing up resources
none of the above
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2/25
Which of the following is the correct syntax for a button click event handler foo?
<button onclick={this.foo()}>
<button onclick={this.foo}>
<button onClick={this.foo()}>
<button onClick={this.foo}>
Next >
3/25
What will happen if you call setState() inside render() method?
Repetitive output appears on the screen
Duplicate key error
Stack overflow error
Nothing happens
Next >
4/25
What is state in React?
A persistant storage.
An internal data store (object) of a component.
Next >
5/25
What is ReactJS?
Server side Framework
User-interface framework
Library for building interaction interfaces
Next >
6/25
React merges the object provided into the current state using ___.
setState()
State()
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7/25
The arbitrary inputs of components are called ___.
Keys
Props
Elements
Ref
Next >
8/25
What is the purpose of the 'key' prop in a React list?
To identify each element uniquely
For styling elements
To enhance performance
To trigger events
Next >
9/25
What does 'PureComponent' do in React?
Manages pure functions
Prevents re-rendering if props and state have not changed
Cleans up the component
Enhances component performance
Next >
10/25
What is the default port where a create-react-app project runs?
3000
8080
5000
8000
Next >
11/25
Which method is necessary to define in a class component in React?
componentDidMount()
shouldComponentUpdate()
render()
getDerivedStateFromProps()
Next >
12/25
What is the purpose of React Router?
To manage global state
For conditional rendering
To handle navigation and routing
To connect to external APIs
Next >
13/25
In React, what is the purpose of the 'Context' API?
To enhance performance
For managing component lifecycle
To share data across components without prop drilling
To handle form inputs
Next >
14/25
What does the 'useMemo' hook do in React?
It memorizes a computed value
It saves memory usage
It recalls previously rendered components
It memorizes the component state
Next >
15/25
What is the use of 'useState' hook in React?
To manage state in functional components
To link state between components
To update state in class components
To store data in the browser's local storage
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16/25
Which of these is a correct way to handle events in React?
<button onClick={this.handleClick}>Click me</button>
<button onClick='handleClick()'>Click me</button>
<button onClick={handleClick()}>Click me</button>
<button handle='onClick'>Click me</button>
Next >
17/25
In which lifecycle method do you make HTTP requests in a class component?
componentDidMount
componentWillMount
componentDidUpdate
componentWillUnmount
Next >
18/25
What is the purpose of the 'useEffect' hook?
To handle state changes
To create a new component
To perform side effects in functional components
To connect to a Redux store
Next >
19/25
What is the purpose of React's 'useCallback' hook?
To memorize a function instance between renders
To call a function as a callback after state changes
To handle API calls efficiently
To update the state based on previous state
Next >
20/25
What is 'prop drilling' in React?
Passing props through multiple layers of components
A method to define PropTypes in a component
Drilling down to find errors in props
A React library for handling properties
Next >
21/25
In React, what is the purpose of the Context API?
To manage global state
To handle HTTP requests
To connect to databases
To optimize performance
Next >
22/25
Which method is the right choice to fetch data in a useEffect hook?
componentDidMount
useFetch
fetch API
getData()
useDataFetching
Next >
23/25
What is the primary use of the React Router library?
Managing state
Routing and navigation
Handling forms
Optimizing performance
Next >
24/25
How do you share state between two components that are not parent-child in React?
Using global variables
Using the Context API
Passing props through intermediate components
Using a state management library like Redux
Next >
25/25
In React, how do you pass data from a parent component to a child component?
Using context
Via global variables
Through props
By setting state in the child
Next >
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