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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
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
3/25 React merges the object provided into the current state using ___.
- setState()
- State()
4/25 Ref is used for referring an element or component returned by ___.
- react()
- render()
- reduce()
- refer()
5/25 In React, which method is used to create a context?
- React.createContext()
- React.createState()
- React.createComponent()
- React.createRef()
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
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 />; }
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
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
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
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
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
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
14/25 Which of these is not a feature of React?
- Virtual DOM
- Server-side rendering
- Built-in HTTP requests
- One-way data binding
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
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
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
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
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
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
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
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 { ... }
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
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
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
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