React Js Detect Operating System of User

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.development.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/17.0.2/umd/react-dom.development.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.26.0/babel.min.js"></script>
</head>
<body>
    <div id="app"></div>
    <script type="text/babel">
        const { useState, useEffect } = React;
        function App() {
            const [os, setOs] = useState('');
            useEffect(() => {
                const detectedOs = detectOS();
                setOs(detectedOs);
            }, []);
            function detectOS() {
                const platform = navigator.platform;
                if (platform.indexOf('Win') !== -1) return 'Windows';
                if (platform.indexOf('Mac') !== -1) return 'Mac OS';
                if (platform.indexOf('Linux') !== -1) return 'Linux';
                if (platform.indexOf('iPhone') !== -1) return 'iOS';
                if (platform.indexOf('Android') !== -1) return 'Android';
                if (platform.indexOf('iPad') !== -1) return 'iPad';
                return 'Unknown';
            }

return (
                <div className="container">
                    <h1>React Js Detect Operating System of User</h1>
                    <p>Operating System: {os}</p>
                </div>
            );
        }

ReactDOM.render(<App />, document.getElementById("app"));
    </script>
    <style>
        * {
            box-sizing: border-box;
        }

.container {
            margin: 0 auto;
            width: 600px;
            text-align: center;
            box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.12), 0 2px 4px 0 rgba(0, 0, 0, 0.24);
            padding: 20px;
        }

h1 {
            font-size: 24px;
            color: #333;
            margin-bottom: 10px;
        }

p {
            font-size: 18px;
            color: #555;
        }
    </style>
</body>

</html>