Here’s the English version of your MDX article on React, translated cleanly with developer-friendly phrasing and markdown intact:

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# Why and How to Use React

**React** is a popular JavaScript library developed by Facebook, used to build dynamic and interactive user interfaces. Thanks to its flexibility and performance, it has become a cornerstone of modern front-end development. In this article, we’ll explore why React is so useful, illustrate its benefits with concrete examples, and show how it transforms the process of building web applications.

## Simplified State Management with React

One of React's key strengths is its efficient state management. Each component in React can maintain its own local state and update independently, making UI changes easier to handle.

**Real-world example: An interactive todo list**

```tsx
import React, { useState } from 'react';

function TodoList() {
  const [tasks, setTasks] = useState([]);
  const [newTask, setNewTask] = useState('');

  const addTask = () => {
    setTasks([...tasks, newTask]);
    setNewTask('');
  };

  return (
    <div>
      <input 
        value={newTask} 
        onChange={(e) => setNewTask(e.target.value)} 
        placeholder="Add a new task"
      />
      <button onClick={addTask}>Add Task</button>
      <ul>
        {tasks.map((task, index) => (
          <li key={index}>{task}</li>
        ))}
      </ul>
    </div>
  );
}

export default TodoList;

In this example, React uses the useState hook to manage task data. Each user interaction updates the state and is instantly reflected in the UI.

Reusable Components for Modular Development

React is built around the concept of components, which let you split a complex interface into independent, reusable, and testable parts. This encourages scalable, maintainable code.

A reusable user card component

function UserCard({ name, email }) {
  return (
    <div className="user-card">
      <h3>{name}</h3>
      <p>{email}</p>
    </div>
  );
}

function App() {
  const users = [
    { name: 'Alice', email: 'alice@example.com' },
    { name: 'Bob', email: 'bob@example.com' },
  ];

  return (
    <div>
      {users.map((user, index) => (
        <UserCard key={index} name={user.name} email={user.email} />
      ))}
    </div>
  );
}

export default App;

By using the UserCard component, we can display multiple users’ info without duplicating code — making the app easier to scale and maintain.

Performance Boost with the Virtual DOM

React improves rendering performance with its Virtual DOM. Instead of updating the browser DOM directly, React performs changes in memory first, then applies only the necessary updates — reducing costly DOM operations.

A real-time filtered product list

import React, { useState } from 'react';

function ProductList() {
  const [search, setSearch] = useState('');
  const products = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry'];

  const filteredProducts = products.filter((product) =>
    product.toLowerCase().includes(search.toLowerCase())
  );

  return (
    <div>
      <input 
        type="text" 
        value={search} 
        onChange={(e) => setSearch(e.target.value)} 
        placeholder="Search products"
      />
      <ul>
        {filteredProducts.map((product, index) => (
          <li key={index}>{product}</li>
        ))}
      </ul>
    </div>
  );
}

export default ProductList;

Here, React only re-renders the relevant parts of the UI as the user types in the search field — thanks to its efficient diffing algorithm and virtual DOM.

Conclusion

React is revolutionizing front-end development through efficient state management, reusable components, and optimized rendering. Whether you're building a simple UI or a complex application, React provides powerful tools for creating modern user experiences. Its rich ecosystem and active community make it an essential tool for any web developer.

Ready to dive deeper into React? Head over to the official documentation and start building your first React apps today!

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