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

191. What is React Native primarily used for?

Answer: Mobile app development

192. In React Native, what is the main programming language used for writing mobile apps?

Answer: JavaScript

193. Which platform(s) can you build mobile apps for using React Native?

Answer: iOS and Android

194. What is the primary advantage of using React Native for mobile app development?

Answer: It allows you to write apps for multiple platforms with a single codebase

195. Which React Native component is used for creating a button?

Answer: <TouchableOpacity>

196. What is the purpose of React Native's "bridge" between JavaScript and native code?

Answer: To facilitate communication between JavaScript and native modules

197. How can you access device features like the camera or GPS in a React Native app?

Answer: By writing custom native modules

198. Which command is commonly used to start a React Native project?

Answer: npx react-native init

199. What is the name of the React Native component that serves as the fundamental building block of UI in an app?

Answer: <View>

200. Which tool can you use to debug and inspect React Native apps while they're running on a device or emulator?

Answer: React Native Debugger
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React Js Multiple Choice Questions React Js MCQ React Js Interview Questions With Answers