Supreme React Test - 72+ MCQs: React test: Evaluate Your Proficiency with React Questions and Answers

1. What is the purpose of the useCallback hook, and when should it be used?

To memoize functions and optimize performance

To manage component state in class components

To handle context API in functional components

To define the initial state of a component

2. What is the purpose of state in React?

To store component properties

To manage component styling

To maintain component history

To manage component data over time

3. Explain the concept of server components in React and how they differ from traditional components.

Server components are components rendered on the server and sent to the client as HTML

Server components are a replacement for the useEffect hook

Server components are used for handling client-side routing in React

Server components have no impact on rendering performance

4. What is the purpose of the React.StrictMode component, and when should it be used?

To define strict coding rules for React components

To optimize rendering performance in React

To catch common coding mistakes and potential issues early

To handle routing in React applications

5. How can you handle conditional rendering in React?

Using the switch statement

Using the if statement

Using ternary operators

Using the map function

6. How can you handle events in React?

By using the onClick event

By using the bind method

By using the addEventListener method

By using the onEvent prop

7. Explain the concept of controlled components in React.

Components that are directly manipulated by the DOM

Components that maintain their own state

Components that rely on Redux for state management

Components that receive props from parent components

8. What is the significance of the 'key' prop in React lists?

It defines the component's identity

It specifies the component's style

It sets the component's position

It helps React identify which items have changed, are added, or are removed

9. How does React Router improve the navigation experience in a React application?

By providing a built-in state management system

By allowing the use of global variables for navigation

By synchronizing the UI with the URL

By preventing the use of dynamic routes

10. What is the purpose of the withRouter HOC in React?

To handle routing

To create higher-order components

To manage component state

To define the component's lifecycle

11. Explain the concept of code splitting in React and how it can improve application performance.

Code splitting is a method for writing concise React components

Code splitting is a feature of React Lazy

Code splitting is a technique to divide the application code into smaller chunks

Code splitting has no impact on application performance

12. What are the benefits of using the React.forwardRef function, and in what scenarios is it useful?

React.forwardRef is used to create higher-order components

React.forwardRef is used for styling React components

React.forwardRef is beneficial for optimizing rendering performance

React.forwardRef allows the parent component to interact with a child's DOM node

13. How does the useTransition hook in React contribute to improving the user experience?

The useTransition hook enhances the transition animations in React

The useTransition hook is used for handling routing in React

The useTransition hook improves the performance of asynchronous operations

The useTransition hook has no impact on the user experience

14. What are Hooks in React, and why were they introduced?

Hooks are functions that let you use state and lifecycle features in functional components

Hooks are event listeners in React

Hooks are a replacement for class components

Hooks are used for styling in React

15. How can you conditionally render elements in React?

Using the if statement

Using the switch statement

Using the map function

Using ternary operators

16. How can you update the state based on the previous state in React?

By using the setState() method

By using the getSnapshotBeforeUpdate method

By using the useReducer hook

By passing a function to the setState() method

17. What is the role of the useRef hook in React?

To create references to DOM elements

To define component properties

To handle context API

To update the virtual DOM

18. How can you pass data from a parent component to a child component in React?

Using refs

Using props

Using state

Using context

19. Explain the role of the React Router Prompt component and when it should be utilized.

The React Router Prompt component is used for handling asynchronous operations

The React Router Prompt component is used to prompt the user before navigating away

The React Router Prompt component defines the initial state of a component

The React Router Prompt component is used for styling React components

20. How does the useDeferredValue hook in React contribute to improving performance, and in what scenarios is it beneficial?

The useDeferredValue hook enhances the transition animations in React

The useDeferredValue hook is used for handling routing in React

The useDeferredValue hook improves the performance of asynchronous operations

The useDeferredValue hook delays the update of a value until after a specified timeout

React MCQ Test 4