Mastering React Concepts

What is the purpose of componentDidMount in React?

• To define the initial state of a component before it mounts.

• To perform actions after a component has been rendered to the DOM.

• To handle user input during the component's lifecycle.

• To update the state of a component before it is rendered.

Which method is called just before a component is removed from the DOM?

• componentDidMount

• render

• shouldComponentUpdate

• componentWillUnmount

What is the primary purpose of state in a React component?

• To store static data that does not change

• To define the structure of a component

• The primary purpose of state in a React component is to manage and store dynamic data that affects the rendering of the component.

• To handle user input events

Which hook is used to manage state in functional components?

• useReducer

• useEffect

• useState

• useContext

What does the useEffect hook do in React?

• useEffect is used for styling components in React.

• The useEffect hook manages side effects in React function components.

• useEffect is a method for managing state in class components.

• useEffect is a hook for handling user input events.

How do you pass data between components in React?

• Use CSS for styling components

• Use HTML attributes for data transfer

• Use local storage for component communication

• Use props for parent-to-child communication and state management libraries for broader data sharing.

What is the purpose of React Router?

• To enhance the performance of React components.

• To provide a state management solution for React apps.

• To manage navigation and routing in React applications.

• To style React applications with CSS frameworks.

What is the Context API used for in React?

• The Context API is used for optimizing performance in React.

• The Context API is used for managing global state and sharing data across components in React.

• The Context API is used for handling form validation in React.

• The Context API is used for routing in React.

How can you optimize performance in a React application?

• Use inline styles for every element

• Increase the size of all components

• Disable all state management features

• Use techniques like memoization, code-splitting, and optimizing component re-renders.

What is the difference between useMemo and useCallback?

• useMemo and useCallback are the same and can be used interchangeably.

• useMemo is for optimizing rendering, while useCallback is for handling events.

• useMemo memoizes values, while useCallback memoizes functions.

• useMemo is used for state management, while useCallback is for side effects.