10 Questions
What is the primary purpose of the useState hook in React?
To manage state changes in a component
React Hooks can only be used in class components.
False
What is the purpose of the key prop in a React component?
To help React keep track of items in a list and improve performance.
The jsx syntax is used to write React components in a _______ way.
declarative
Match the following React lifecycle methods with their purpose:
componentDidMount = Called when the component is mounted to the DOM
componentWillUnmount = Called when the component is about to be unmounted from the DOM
render = Called when the component is rendered to the DOM
shouldComponentUpdate = Called when the component's props or state change
What is the main difference between a controlled and uncontrolled component in React?
A controlled component's value is managed by the state, whereas an uncontrolled component's value is managed by the DOM.
How does React's Virtual DOM improve the performance of a React application?
React's Virtual DOM improves performance by only re-rendering the components that have changed, reducing the number of DOM mutations and resulting in faster rendering.
What is the purpose of the shouldComponentUpdate lifecycle method in React?
The shouldComponentUpdate method determines whether a component should re-render when its props or state change.
What is the difference between a functional component and a class component in React?
A functional component is a pure function that takes in props and returns JSX, whereas a class component is a class that extends the React Component class and has its own lifecycle methods.
How does React's context API help in sharing data between components?
React's context API helps in sharing data between components by providing a way to share data between components without having to pass props down manually.
Test your knowledge of React JS with these questions about React Hooks, JSX, and lifecycle methods. See how well you understand React components and their applications.
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