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

61. What is React state management primarily used for?

Answer: Managing application state

62. Which built-in method in a React class component is used to initialize the component's state?

Answer: constructor

63. In React, which method is used to update the component's state and trigger a re-render?

Answer: setState

64. What is the primary benefit of using state management libraries like Redux in a React application?

Answer: Centralizing and managing application state

65. In a functional component, how do you manage state using React Hooks?

Answer: By using the useState Hook

66. What is the purpose of the useReducer Hook in React state management?

Answer: To manage complex state logic

67. Which of the following is NOT a common state management library for React?

Answer: GraphQL

68. What is the main principle behind "unidirectional data flow" in React state management?

Answer: Data flows from components to a central store

69. In Redux, what is the central component responsible for managing the application state?

Answer: Store

70. Which Redux function is used to dispatch actions to update the state in a Redux store?

Answer: dispatch
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React Js Multiple Choice Questions React Js MCQ React Js Interview Questions With Answers