Learn React Js MCQs
Prepare React Js MCQs (Multiple choice Questions) for exam and job interviews.
What is the purpose of `useEffect` hook in React?
1) To manage component states
2) To handle events
3) To perform side effects in function components
4) To fetch data
Answer : Option 3
How do you create a functional component in React?
1) By using `React.Component`
2) By using `function` keyword
3) By using `createComponent` method
4) By using `class` keyword
Answer : Option 2
What is the virtual DOM in React?
1) A copy of the real DOM
2) A custom implementation of the DOM
3) A lightweight representation of the real DOM
4) A debugging tool for the DOM
Answer : Option 3
How do you pass data from parent to child components in React?
1) Using state
2) Using refs
3) Using props
4) Using context
Answer : Option 3
What does JSX stand for?
1) JavaScript XML
2) Java Syntax
3) JavaScript Extension
4) Java Source
Answer : Option 1
How do you conditionally render elements in React?
1) Using `if-else` statements
2) Using `switch-case` statements
3) Using ternary operators or logical &&
4) Using `for` loops
Answer : Option 3
What is the purpose of `React.Fragment`?
1) To group multiple elements without adding extra nodes to the DOM
2) To return multiple elements
3) To render components asynchronously
4) To replace a component
Answer : Option 1
How do you handle forms in React?
1) Using `document.getElementById`
2) Using the `useState` hook
3) Using the `useEffect` hook
4) Using `onSubmit` event
Answer : Option 4
What is the purpose of `key` prop in React?
1) To style elements
2) To set attributes
3) To uniquely identify elements in a list
4) To bind data
Answer : Option 3
How do you lift state up in React?
1) By using the `useEffect` hook
2) By using the `useContext` hook
3) By moving the state to a common ancestor component
4) By using the `useState` hook
Answer : Option 3