React has become one of the most popular JavaScript libraries for building user interfaces due to its simplicity, flexibility, and efficiency. In this article, we will explore the fundamentals of React, including JSX, components, props, state, and lifecycle methods, and provide illustrative examples to help you understand these key concepts. 1. JSX (JavaScript XML) JSX is a syntax extension for JavaScript that allows you to write UI components using a syntax that closely resembles HTML. It provides a more readable and concise way to describe the UI components. const element = <h1>Hello, World!</h1>; ReactDOM.render(element, document.getElementById('root')); 2. Components and Props React components are the building blocks of a React application. They are reusable and encapsulate the UI logic. Props are used to pass data from parent to child components. const Welcome = (props) => { return <h1>Hello, {props.name}</h1>; }; ReactDOM.render(<Welcome name="John" />, document.getElementById('root')); 3. State and Lifecycle State allows React components to create and manage their own data. Lifecycle methods are special methods that execute at specific phases in a component's lifecycle. class Clock extends React.Component { constructor(props) { super(props); this.state = { date: new Date() }; } componentDidMount() { this.timerID = setInterval(() => this.tick(), 1000); } componentWillUnmount() { clearInterval(this.timerID); } tick() { this.setState({ date: new Date() }); } render() { return <h2>It is {this.state.date.toLocaleTimeString()}.</h2>; } } ReactDOM.render(<Clock />, document.getElementById('root')); 4. Handling Events React events are named using camelCase, rather than lowercase. With JSX, you pass a function as the event handler, rather than a string. class Toggle extends React.Component { constructor(props) { super(props); this.state = { isToggleOn: true }; }…