index.html and main.jsx

The only HTML page. React renders everything inside <div id="root">. The script tag loads main.jsx.

<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>My App</title>
  </head>
  <body>
    <div id="root"></div>
    <script type="module" src="/src/main.jsx"></script>
  </body>
</html>

The entry point. It finds the root div and renders the App component into it. StrictMode enables extra development checks (it renders components twice in development to find bugs).

import { StrictMode } from 'react';
import { createRoot } from 'react-dom/client';
import './index.css';
import App from './App.jsx';

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