250+ React Js MCQ With Online Practice Test

React.js, often simply called React, is a highly popular JavaScript library for building user interfaces. Developed and maintained by Facebook, React is renowned for its component-based architecture and the ability to efficiently update and render components when data changes. It is a foundational tool for developing modern web and mobile applications, allowing developers to create dynamic and interactive user interfaces with ease. React's vast ecosystem, including tools like React Native for mobile app development, makes it a top choice for frontend development and a key player in the world of web technologies.

Practice Test

201. What is React's primary purpose in web development?

Answer: To create user interfaces

202. Which JavaScript library is often used in conjunction with React for state management?

Answer: Redux

203. In React, what is JSX short for?

Answer: JavaScript XML

204. Which command is used to create a new React application using Create React App (CRA)?

Answer: create-react-app

205. Which component lifecycle method is called just before a component is removed from the DOM?

Answer: componentWillUnmount

206. What is the primary function of React Router in a React application?

Answer: To manage client-side routing

207. What is the role of Babel in the React ecosystem?

Answer: To compile JSX to JavaScript

208. Which package manager is commonly used for managing React projects and dependencies?

Answer: Yarn

209. In the context of React, what does "props" stand for?

Answer: Properties

210. Which of the following is not a valid React component type in the React ecosystem?

Answer: Redux components
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React Js Multiple Choice Questions React Js MCQ React Js Interview Questions With Answers