ReactJS Interview Question and Answers
ReactJS Interview Question and Answers: ReactJS is an open-source JavaScript library that is primarily used for building user interfaces. It was developed by Facebook and is now maintained by Facebook and a community of individual developers and companies.
ReactJS Interview Question and Answers: ReactJS allows developers to create reusable UI components and efficiently update and render those components as the data changes. It follows a declarative programming approach, which means that developers only need to specify what they want the UI to look like and React takes care of the rest. ReactJS is widely used in web development, and its popularity has grown significantly due to its performance, scalability, and ease of use. It also integrates well with other technologies, making it a versatile tool for creating modern web applications, Here we are Providing Important ReactJS Interview Question and Answers.
Question 1. What is ReactJS?
Answer: ReactJS is an open-source JavaScript library used for building user interfaces or UI components. It was developed by Facebook and is now maintained by Facebook and a community of individual developers and companies.
Question 2. What is the difference between state and props in ReactJS?
Answer: State is a built-in feature in ReactJS used for managing component data that changes over time. Props, on the other hand, are short for “properties” and are used for passing data from a parent component to a child component.
Question 3. What is the Virtual DOM in ReactJS?
Answer: The Virtual DOM is an abstraction of the browser’s real DOM in ReactJS. Instead of updating the entire DOM every time there is a change, ReactJS updates the Virtual DOM, and then only updates the part of the real DOM that needs to be changed. This makes ReactJS more efficient and faster than traditional methods.
Question 4. What is JSX in ReactJS?
Answer: JSX is a syntax extension for JavaScript that allows developers to write HTML-like code in their JavaScript files. It is used to describe the UI components in ReactJS and makes it easier to work with them.
Question 5. What is the significance of keys in ReactJS?
Answer: Keys are a unique identifier for each element in an array in ReactJS. They help ReactJS keep track of which items have changed, been added, or been removed from the array, which improves performance and helps prevent errors.
Question 6. What is Redux in ReactJS?
Answer: Redux is a state management library for ReactJS. It provides a predictable state container that makes it easier to manage the state of an application and share data between components.
Question 7. What is the role of the componentDidMount() lifecycle method in ReactJS?
Answer: The componentDidMount() method is called after a component is mounted in the DOM. It is used to perform any necessary setup, such as fetching data from a server or initializing a third-party library.
Question 8. How would you optimize the performance of a ReactJS application?Answer: There are several ways to optimize the performance of a ReactJS application, including using the Virtual DOM, minimizing unnecessary renders, using server-side rendering, and optimizing images and other assets. Additionally, it’s important to avoid using inefficient algorithms and data structures, and to keep the code clean and maintainable.
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