PWA Installability Essentials

1. Introduction

Progressive Web Apps (PWAs) are web applications that enhance the user experience through modern web capabilities. This lesson covers the essentials for making PWAs installable, focusing on the key components that enable users to add these apps to their home screens.

2. Key Concepts

3. Installability Criteria

To make a PWA installable, it must fulfill the following criteria:

• The site must be served over HTTPS.
• A valid Web App Manifest must be provided.
• There must be a registered service worker controlling the site.
• The app must be responsive and fit the screen size of the device.

4. Web App Manifest

The Web App Manifest is a JSON file that provides information about the app, including its name, icons, start URL, and display type. The manifest allows the app to be recognized as a PWA.

{
    "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"
        }
    ]
}

5. Service Worker

A service worker is a script that your browser runs in the background, separate from a web page. It enables features such as push notifications and caching for offline use.

if ('serviceWorker' in navigator) {
    window.addEventListener('load', function() {
        navigator.serviceWorker.register('/service-worker.js').then(function(registration) {
            console.log('ServiceWorker registration successful with scope: ', registration.scope);
        }, function(error) {
            console.log('ServiceWorker registration failed: ', error);
        });
    });
}

6. Best Practices

To ensure a smooth user experience and enhance installability, follow these best practices:

• Ensure fast loading times.
• Optimize images and resources.
• Test on various devices and browsers.
• Keep the manifest and service worker updated.

7. FAQ