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.
Show All Answers
Practice Test
201. What is React's primary purpose in web development?
A. To manage server-side logic
B. To create user interfaces
C. To store and manage data
D. To handle server requests
Show Answer
Report This Question
Answer: To create user interfaces
202. Which JavaScript library is often used in conjunction with React for state management?
A. Redux
B. jQuery
C. Lodash
D. Express
Show Answer
Report This Question
Answer: Redux
203. In React, what is JSX short for?
A. JavaScript XML
B. JavaScript Extension
C. JavaScript Syntax
D. JavaScript Extended
Show Answer
Report This Question
Answer: JavaScript XML
204. Which command is used to create a new React application using Create React App (CRA)?
A. create-react-app
B. npm install react
C. react init app
D. npm create-react
Show Answer
Report This Question
Answer: create-react-app
205. Which component lifecycle method is called just before a component is removed from the DOM?
A. componentWillUnmount
B. componentDidMount
C. componentWillUpdate
D. componentDidUpdate
Show Answer
Report This Question
Answer: componentWillUnmount
206. What is the primary function of React Router in a React application?
A. To handle server requests
B. To create reusable UI components
C. To manage client-side routing
D. To manage API requests
Show Answer
Report This Question
Answer: To manage client-side routing
207. What is the role of Babel in the React ecosystem?
A. To compile JSX to JavaScript
B. To create React components
C. To manage application state
D. To handle server requests
Show Answer
Report This Question
Answer: To compile JSX to JavaScript
208. Which package manager is commonly used for managing React projects and dependencies?
A. npm
B. Yarn
C. Bower
D. Grunt
Show Answer
Report This Question
Answer: Yarn
209. In the context of React, what does "props" stand for?
A. Properties
B. Procedures
C. Prototypes
D. Parameters
Show Answer
Report This Question
Answer: Properties
210. Which of the following is not a valid React component type in the React ecosystem?
A. Functional components
B. Class components
C. Redux components
D. Higher-order components
Show Answer
Report This Question
Answer: Redux components