React Quiz

What is React?

• A library for building user interfaces

• A programming language

• A database management system

• A CSS framework

What is JSX in React?

• A syntax extension for JavaScript

• A new programming language

• A tool for debugging React apps

• A CSS preprocessor

Which method is used to render a React component to the DOM?

• `React.renderComponent`

• `ReactDOM.render`

• `React.componentRender`

• `ReactDOM.create`

What is a React component?

• A function or class that returns UI elements

• A database model

• A backend API

• A CSS module

What is the virtual DOM?

• A lightweight representation of the real DOM

• A feature of browsers to optimize rendering

• A server-side rendering tool

• None of the above

What does the `useState` hook do?

• Manages lifecycle methods

• Provides access to the Redux store

• Adds state management to functional components

• Handles side effects

What does `useState` return?

• A value and a function to update it

• A promise and a callback

• A single value only

• An array of all state variables

const [count, setCount] = useState(0);

How do you initialize state using `useState`?

• State is initialized to 0

• State is initialized to null

• State is not initialized

• State is initialized to a function

setState(newValue);
Which of the following updates the state value in `useState`?

• Directly assigning a value to the state variable

• Using the `setState` function provided by `useState`

• Modifying the state variable directly

• None of the above

What happens if you call the updater function from `useState` multiple times in one render?

• Only the last state change takes effect

• All state changes are merged

• Only the first state change takes effect

• State changes throw an error