React JS MCQs 7

What is the purpose of the useRef hook in React?

• a) To create references to DOM elements or React components (Correct Answer)
• b) To manage component state
• c) To subscribe to context changes
• d) To perform asynchronous operations

In React, what is the recommended way to handle forms?

• a) Using regular HTML form elements
• b) Using controlled components where form data is handled by React state (Correct Answer)
• c) Using uncontrolled components where form data is handled by the DOM
• d) Using Redux for form state management

Which hook is used to perform side effects in functional components?

• a) useState
• b) useEffect (Correct Answer)
• c) useContext
• d) useReducer

What is the purpose of the useContext hook in React?

• a) To manage component state
• b) To handle context within class components
• c) To access context values in functional components (Correct Answer)
• d) To fetch data from an external API

In React, which method is called before the component is removed from the DOM?

• a) componentWillUnmount (Correct Answer)
• b) componentDidMount
• c) componentDidUpdate
• d) componentWillMount

What is the primary role of ReactDOM in a React application?

• a) To handle routing and navigation
• b) To manage global application state
• c) To render React components into the DOM (Correct Answer)
• d) To handle server-side rendering

What is the purpose of the useMemo hook in React?

• a) To memoize the result of a function so that it is only recomputed when its dependencies change (Correct Answer)
• b) To perform side effects in functional components
• c) To manage component state
• d) To subscribe to context changes

In React, what does it mean to lift state up?

• a) It refers to managing state at the lowest level of the component tree
• b) It refers to passing state from child to parent components
• c) It refers to moving state to a common ancestor component to share it between sibling components (Correct Answer)
• d) It refers to removing state from a component

What is the purpose of the defaultProps property in a React component?

• a) To define default values for props (Correct Answer)
• b) To set the initial state of a component
• c) To define the default styling for a component
• d) To handle default event behavior

In React, what is the purpose of the key prop when rendering a list of components?

• a) It defines the style of each list item
• b) It helps React identify which items have changed, are added, or are removed in the list (Correct Answer)
• c) It sets the initial state of each list item
• d) It specifies the order of the list items