Learn React Js MCQs
Prepare React Js MCQs (Multiple choice Questions) for exam and job interviews.
What is a key benefit of using JSX in React?
1) It automatically manages state
2) It provides server-side rendering
3) It provides a clear, readable syntax for defining UI structures
4) It handles routing
Answer : Option 3
What is the purpose of the `useImperativeHandle` hook?
1) To manage state
2) To customize the instance value that is exposed to parent components when using refs
3) To handle side effects
4) To optimize performance
Answer : Option 2
How do you update state based on previous state in a functional component?
1) Using `setState` directly
2) Using a callback function in `setState`
3) Using the `useReducer` hook
4) Using `useContext`
Answer : Option 2
What is the purpose of the `React.Children` utility?
1) To clone elements
2) To map over children components
3) To handle side effects
4) To manage state
Answer : Option 2
How do you access props in a class component?
1) Using `this.props`
2) Using `this.state`
3) Using `this.context`
4) Using `this.refs`
Answer : Option 1
What does the `useLayoutEffect` hook do?
1) Executes a function after all DOM mutations
2) Handles side effects after rendering
3) Manages component state
4) Optimizes performance
Answer : Option 1
How do you prevent a component from rendering?
1) Using `componentDidUpdate`
2) Returning `null` in the `render` method
3) Using `useMemo`
4) Using `useEffect`
Answer : Option 2
What is the purpose of the `getDerivedStateFromProps` lifecycle method?
1) To handle side effects
2) To update the state based on props
3) To prevent rendering
4) To manage context
Answer : Option 2
How do you force a component to re-render?
1) Using `this.forceUpdate()`
2) Using `this.setState()`
3) Using `useEffect`
4) Using `useState`
Answer : Option 1
What is the purpose of the `componentDidCatch` lifecycle method?
1) To handle side effects
2) To catch errors in the component tree
3) To update the state
4) To manage props
Answer : Option 2