What is React and why is it used? React क्या है और इसे क्यों use करते हैं?

React is a JavaScript library developed by Facebook for building user interfaces with reusable components. It uses a virtual DOM for efficient updates and enables building interactive single-page applications (SPAs).

// Creating a basic React component
import React from 'react';
import ReactDOM from 'react-dom';

function App() {
    return (
        <div>
            <h1>Welcome to React!</h1>
            <p>React makes building UI easy and fun.</p>
        </div>
    );
}

// Rendering the component
ReactDOM.render(<App />, document.getElementById('root'));

// With React 18
import { createRoot } from 'react-dom/client';

const root = createRoot(document.getElementById('root'));
root.render(<App />);

// Why React?
// 1. Reusable components reduce code duplication
// 2. Virtual DOM improves performance
// 3. One-way data binding makes code predictable
// 4. Large community and ecosystem
// 5. Easy to learn and master
// 6. Used by major companies (Facebook, Netflix, Airbnb)