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

171. Which tool is commonly used for inspecting and debugging React components in the browser?

Answer: React DevTools

172. In React DevTools, what is the purpose of the "Components" tab?

Answer: To browse and inspect React component tree

173. What does the "Props" panel in React DevTools display?

Answer: The properties and values of a component

174. In React DevTools, what does the "State" panel show for a selected component?

Answer: The component's local state

175. How can you open React DevTools in a web application?

Answer: By using the browser's built-in developer tools

176. What does the "Profiler" tab in React DevTools help you analyze?

Answer: Component rendering performance

177. What is the purpose of the "Hooks" tab in React DevTools?

Answer: To browse and inspect the component tree using hooks

178. In React DevTools, what does the "DOM" tab show?

Answer: The Document Object Model (HTML structure)

179. Which of the following statements about React DevTools is true?

Answer: It's a separate application from the browser's developer tools

180. What does the "Settings" tab in React DevTools allow you to configure?

Answer: Custom keyboard shortcuts
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React Js Multiple Choice Questions React Js MCQ React Js Interview Questions With Answers