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React Basics

1/25 React is mainly used for building ___.
- Database
- Connectivity
- User interface
- Design Platform
2/25 Which of the following methods in a React Component should be overridden to stop the component from updating?
- willComponentUpdate
- shouldComponentUpdate
- componentDidUpdate
- componentDidMount
3/25 Which of the following methods in a React Component is called after the component is rendered for the first time?
- componentDidUpdate
- componentDidMount
- componentMounted
- componentUpdated
4/25 How do you write an inline style which specifies the font-size:12px and color:red; in JSX?
- style={{font-size:12,color:'red'}}
- style={{fontSize:'12px',color:'red'}}
- style={fontSize:'12px',color:'red'}
- style={{font-size:12px,color:'red'}}
5/25 What is ReactJS?
- Server side Framework
- User-interface framework
- Library for building interaction interfaces
6/25 What disadvantages does ReactJS have?
- It is only a view layer. You have to plug your code for Ajax requests, events and so on.
- The library is pretty large.
- The learning curve can be slow.
- All of the above options
7/25 How do you create a ref in a class component in React?
- React.createRef()
- React.ref()
- this.ref.create()
- new Ref()
8/25 What is a higher-order component in React?
- A component that renders other components
- A component with higher z-index
- A stateful component
- A component with higher-order functions
9/25 Which of the following is not a lifecycle method in React?
- componentDidMount
- shouldComponentRender
- componentWillUnmount
- getSnapshotBeforeUpdate
10/25 What is the purpose of React Router?
- To manage global state
- For conditional rendering
- To handle navigation and routing
- To connect to external APIs
11/25 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
12/25 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' />
13/25 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
14/25 What does 'props.children' represent in a React component?
- The state of the parent component
- The children passed to the component
- A type of React child component
- The props of the child components
15/25 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
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 How does React handle form submission?
- Using an event handler on the form element
- By automatically sending a POST request
- Using a dedicated React form submission library
- React cannot handle form submissions
18/25 What does 'lifting state up' mean in React?
- Moving state to a common ancestor of components that need it
- Increasing the performance of the state updates
- Automatically handling state changes in child components
- Transferring state to a higher-order component
19/25 What does 'prop drilling' refer to in React?
- Passing props to deep child components
- Setting default prop values
- Validating prop types
- Updating props from child components
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 How do you handle form submissions in React?
- Using an onSubmit event handler
- With a dedicated form management library
- By directly submitting to the server
- React does not support form submissions
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 Which of the following is a React hook?
- useComponent
- useState
- useReact
- useElement
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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