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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
2/25 ___ can be done while multiple elements need to be returned from a component.
- Abstraction
- Packing
- Insulation
- Wrapping
3/25 Which of the following methods in a React Component should be overridden to stop the component from updating?
- willComponentUpdate
- shouldComponentUpdate
- componentDidUpdate
- componentDidMount
4/25 What advantages does ReactJS have?
- Increases the application’s performance with Virtual DOM
- JSX makes a code that is easy to read and write
- It renders both on client and server side
- Easy to integrate with other frameworks(Angular, BackboneJS) since it is only a view library
- All of the above
5/25 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
6/25 React merges the object provided into the current state using ___.
- setState()
- State()
7/25 Ref is used for referring an element or component returned by ___.
- react()
- render()
- reduce()
- refer()
8/25 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
9/25 How do you create a ref in a class component in React?
- React.createRef()
- React.ref()
- this.ref.create()
- new Ref()
10/25 Which of the following is not a lifecycle method in React?
- componentDidMount
- shouldComponentRender
- componentWillUnmount
- getSnapshotBeforeUpdate
11/25 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
12/25 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
13/25 How do you pass a prop named 'data' to a component named 'MyComponent'?
- <MyComponent data={this.props.data} />
- <MyComponent props={data} />
- <MyComponent>{data}</MyComponent>
- <MyComponent data='data' />
14/25 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
15/25 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>
16/25 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
17/25 In which lifecycle method do you make HTTP requests in a class component?
- componentDidMount
- componentWillMount
- componentDidUpdate
- componentWillUnmount
18/25 What does 'React.Fragment' do?
- It groups a list of children without adding extra nodes to the DOM
- It is a method to optimize performance
- It is used to fragment a component into smaller components
- It is a way to render components asynchronously
19/25 In which scenario would you use React's 'useRef' hook?
- To directly interact with a DOM element
- To update the component's state
- To fetch data from an API
- To create a new React component
20/25 How do you optimize performance for a list of items in React that are frequently re-rendered?
- Using shouldComponentUpdate
- Using PureComponent
- Using React.memo
- Using useState
- Using useEffect
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
22/25 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
23/25 How can you prevent a function from being called too frequently in React, such as during window resizing?
- Using shouldComponentUpdate
- Using PureComponent
- Using debounce or throttle techniques
- Using useEffect with an empty dependency array
24/25 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
25/25 Which of the following is a React hook?
- useComponent
- useState
- useReact
- useElement
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