PWA Fundamentals Topic 27

Introduction

Progressive Web Apps (PWAs) are web applications that provide a native-like experience to users. They utilize modern web capabilities to deliver an app-like experience directly through the web browser.

Key Concepts

• Responsive Design: PWAs must work on any device, regardless of screen size.
• Connectivity Independence: They should work offline or on low-quality networks.
• App-like Experience: Users should feel like they are using a native app.
• Freshness: Content should always be up-to-date.
• Secure: PWAs must be served over HTTPS.
• Discoverable: They should be identifiable as applications, allowing search engines to find them.
• Installable: Users should be able to add them to their home screen.
• Linkable: They should have a unique URL to share easily.

Service Workers

Service workers are scripts that run in the background, separate from a web page, and enable features such as push notifications and background sync.

Steps to Register a Service Worker

if ('serviceWorker' in navigator) {
    window.addEventListener('load', function() {
        navigator.serviceWorker.register('/sw.js').then(function(registration) {
            console.log('Service Worker registered with scope:', registration.scope);
        }).catch(function(error) {
            console.log('Service Worker registration failed:', error);
        });
    });
}
                

Web App Manifest

The web app manifest is a JSON file that provides information about the application (name, author, icon, etc.) in a simple JSON format.

Example Manifest File

{
    "name": "My PWA",
    "short_name": "PWA",
    "start_url": "/index.html",
    "display": "standalone",
    "background_color": "#ffffff",
    "theme_color": "#000000",
    "icons": [
        {
            "src": "icon-192x192.png",
            "sizes": "192x192",
            "type": "image/png"
        },
        {
            "src": "icon-512x512.png",
            "sizes": "512x512",
            "type": "image/png"
        }
    ]
}
                

Best Practices

1. Use HTTPS for secure communication.
2. Ensure the app works offline using caching strategies.
3. Optimize for performance to enhance user experience.
4. Test on various devices and browsers to ensure compatibility.

FAQ