React.js is a popular open-source JavaScript library used for building user interfaces (UIs) or web applications. It was developed by Facebook and is widely used in industry. React.js allows developers to build reusable UI components and makes it easier to manage the state of the application. Additionally, React.js is highly performant due to its virtual DOM (Document Object Model) which allows it to efficiently update only the necessary parts of the UI when there is a change in the application state. In this article, we will explore the basics of React.js, its features, and best practices for developing efficient and reusable user interfaces. Basics of React.js JSX (JavaScript XML): JSX is a syntax extension for JavaScript, which allows us to write HTML-like code in JavaScript. It makes it easier to write and maintain UI components in React.js. JSX elements are transformed into JavaScript function calls, which React.js uses to create the virtual DOM. Here is an example of a JSX eleme...