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
61. What is React state management primarily used for?
A. Handling server-side data
B. Managing component rendering
C. Managing application state
D. Fetching data from APIs
Show Answer
Report This Question
Answer: Managing application state
62. Which built-in method in a React class component is used to initialize the component's state?
A. componentDidMount
B. constructor
C. render
D. setState
Show Answer
Report This Question
Answer: constructor
63. In React, which method is used to update the component's state and trigger a re-render?
A. render
B. setState
C. componentWillUnmount
D. componentDidMount
Show Answer
Report This Question
Answer: setState
64. What is the primary benefit of using state management libraries like Redux in a React application?
A. Simplifying component rendering
B. Centralizing and managing application state
C. Handling server-side rendering
D. Optimizing component lifecycle
Show Answer
Report This Question
Answer: Centralizing and managing application state
65. In a functional component, how do you manage state using React Hooks?
A. By using the constructor method
B. By directly modifying the state variable
C. By using the useState Hook
D. By creating a separate state function
Show Answer
Report This Question
Answer: By using the useState Hook
66. What is the purpose of the useReducer Hook in React state management?
A. To fetch data from APIs
B. To manage component rendering
C. To manage complex state logic
D. To define a new route
Show Answer
Report This Question
Answer: To manage complex state logic
67. Which of the following is NOT a common state management library for React?
A. Redux
B. MobX
C. GraphQL
D. Zustand
Show Answer
Report This Question
Answer: GraphQL
68. What is the main principle behind "unidirectional data flow" in React state management?
A. Data flows from components to a central store
B. Data flows from the central store to components
C. Data flows in multiple directions
D. Data flows only in functional components
Show Answer
Report This Question
Answer: Data flows from components to a central store
69. In Redux, what is the central component responsible for managing the application state?
A. Reducer
B. Middleware
C. Store
D. Action
Show Answer
Report This Question
Answer: Store
70. Which Redux function is used to dispatch actions to update the state in a Redux store?
A. getState
B. dispatch
C. subscribe
D. mapStateToProps
Show Answer
Report This Question
Answer: dispatch
