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React Basics
1/25
___ can be done while multiple elements need to be returned from a component.
Abstraction
Packing
Insulation
Wrapping
Next >
2/25
Choose the right answer about JSX.
JSX is faster as it performs optimization while compiling code to JavaScript
JSX is a syntax notation for JavaScript XML
JSX provides expressiveness of JavaScript along with HTML, like template syntax
All of the above options
Next >
3/25
React merges the object provided into the current state using ___.
setState()
State()
Next >
4/25
Ref is used for referring an element or component returned by ___.
react()
render()
reduce()
refer()
Next >
5/25
In React, which method is used to create a context?
React.createContext()
React.createState()
React.createComponent()
React.createRef()
Next >
6/25
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 >
7/25
What is the correct syntax for a functional component in React?
function MyComponent() { return <div />; }
class MyComponent extends React.Component { render() { return <div />; }}
const MyComponent = () => { return <div />; }
var MyComponent = function() { return <div />; }
Next >
8/25
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 >
9/25
What is a Fragment in React?
A part of the component state
A tool for memoization
A component that can return multiple elements
A higher-order component
Next >
10/25
What is the purpose of 'PropTypes' in React?
To specify the types of props a component can receive
To document the component code
To improve performance
To provide default values to props
Next >
11/25
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
Next >
12/25
What is a 'prop' in React?
A function inside a component
A state variable in a component
A read-only attribute used in a component
A style attribute of HTML elements
Next >
13/25
How do you conditionally render components in React?
Using if-else statements inside JSX
Using the ternary operator inside JSX
Using for loop inside JSX
Using switch-case inside JSX
Next >
14/25
Which of these is not a feature of React?
Virtual DOM
Server-side rendering
Built-in HTTP requests
One-way data binding
Next >
15/25
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 >
16/25
What is the significance of keys in React lists?
They are used for styling purposes
They help React identify which items have changed, are added, or are removed
They represent the unique ID of each element
They increase the performance of list rendering
Next >
17/25
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 >
18/25
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 >
19/25
What is the purpose of the 'key' prop in React lists?
To enhance performance
To uniquely identify each element
For styling
To enable React's virtual DOM
Next >
20/25
What is the purpose of 'useReducer' in React?
To handle component lifecycle
For state management using a reducer function
To reduce the bundle size of a React app
To optimize rendering performance
Next >
21/25
What is JSX in React?
A JavaScript-based styling language
A syntax extension for JavaScript
A new programming language based on JavaScript
A framework for building user interfaces
Next >
22/25
Which is a valid way to create a component in React?
function MyComponent() { return <div/>; }
new ReactComponent(MyComponent)
React.createComponent(MyComponent)
class MyComponent extends ReactElement { ... }
Next >
23/25
What are 'fragments' in React?
Tools for memory management
Components that return multiple elements
A pattern for prop validation
Parts of the component's state
Next >
24/25
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 >
25/25
What is the use of the 'useEffect' hook in React?
To manage component state
To perform side effects in functional components
For rendering optimizations
To create reusable components
Next >
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