React has become one of the most popular front-end JavaScript frameworks in recent years. If you're looking for a job that involves React, you're likely to encounter some tough interview questions.
In this article, we'll go over some of the most common React interview questions and how to answer them.
1. What is React?
React is a JavaScript library for building user interfaces. It lets you create reusable components so that your code is easy to read and maintain.
2. What are the benefits of using React?
There are many benefits to using React, including:
- Easy to learn and use
- Fast and efficient
- Scalable
- Maintainable
- Easy to test
3. What is a React component?
A React component is a reusable piece of code that can be used to create a user interface. Components can be written in JavaScript or in a language called JSX.
4. What is JSX?
JSX is a syntax extension to JavaScript. It allows you to write HTML-like code in your JavaScript files.
5. What is the difference between a React component and a React element?
A React element is a plain JavaScript object that represents a DOM node. A React component is a React element with additional functionality.
6. What is the difference between a stateless and a stateful React component?
Stateless React components are functions that take props and return React elements. Stateful React components are classes that extend React.Component.
7. What is a React prop?
A React prop is a JavaScript object that is passed to a React component. Props are used to pass data and event handlers to components.
8. What is a React state?
A React state is a JavaScript object that is used to store data for a React component. States are mutable, which means they can be changed over time.
9. What is a React event?
A React event is a synthetic event that is triggered by a browser or by a React component. Event handlers can be attached to components to handle events.
10. What is a React lifecycle method?
A React lifecycle method is a function that is invoked at a specific phase of a component's life. Lifecycle methods can be used to initialize and teardown a component.
11. What is a React fragment?
A React fragment is a piece of code that represents a DOM node. Fragments can be used to group a set of children without adding extra nodes to the DOM.
12. What is a React portal?
A React portal is a way to render a React component outside of the normal DOM hierarchy. Portals can be used to render modals and tooltips.
13. What is a React context?
A React context is an object that is used to store data that can be accessed by all components in a React component tree. Contexts are used to avoid prop drilling.
14. What is a React higher-order component?
A React higher-order component is a function that takes a React component and returns a new React component. Higher-order components can be used to add functionality to existing components.
15. What is a React memo?
A React memo is a way to memorize a React component so that it is only re-rendered if its props have changed. Memos can improve the performance of React applications.
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