Progressive Web Apps
Web App Manifest
{
"name": "My App",
"short_name": "MyApp",
"start_url": "/",
"display": "standalone",
"background_color": "#ffffff",
"theme_color": "#000000",
"icons": [
{ "src": "/icons/192.png", "sizes": "192x192", "type": "image/png" },
{ "src": "/icons/512.png", "sizes": "512x512", "type": "image/png", "purpose": "any maskable" }
]
}
<link rel="manifest" href="/manifest.json" />
<meta name="theme-color" content="#000000" />
<link rel="apple-touch-icon" href="/icons/192.png" />
Service Worker (Workbox — recommended)
// sw.ts (using Workbox)
import { precacheAndRoute } from 'workbox-precaching';
import { registerRoute } from 'workbox-routing';
import { CacheFirst, NetworkFirst, StaleWhileRevalidate } from 'workbox-strategies';
import { ExpirationPlugin } from 'workbox-expiration';
// Precache app shell
precacheAndRoute(self.__WB_MANIFEST);
// Cache-first for static assets
registerRoute(
({ request }) => request.destination === 'image' || request.destination === 'font',
new CacheFirst({
cacheName: 'static-assets',
plugins: [new ExpirationPlugin({ maxEntries: 100, maxAgeSeconds: 30 * 24 * 60 * 60 })],
})
);
// Network-first for API calls
registerRoute(
({ url }) => url.pathname.startsWith('/api/'),
new NetworkFirst({
cacheName: 'api-cache',
plugins: [new ExpirationPlugin({ maxEntries: 50, maxAgeSeconds: 5 * 60 })],
})
);
// Stale-while-revalidate for pages
registerRoute(
({ request }) => request.mode === 'navigate',
new StaleWhileRevalidate({ cacheName: 'pages' })
);
Registration
if ('serviceWorker' in navigator) {
window.addEventListener('load', async () => {
const registration = await navigator.serviceWorker.register('/sw.js');
console.log('SW registered:', registration.scope);
});
}
Offline Fallback
// In service worker
import { setCatchHandler } from 'workbox-routing';
setCatchHandler(async ({ event }) => {
if (event.request.destination === 'document') {
return caches.match('/offline.html');
}
return Response.error();
});
Caching Strategies
| Strategy |
Use For |
Freshness |
| Cache First |
Static assets, fonts, images |
Stale OK |
| Network First |
API data, dynamic pages |
Fresh preferred |
| Stale While Revalidate |
Semi-dynamic content |
Stale, updating |
| Network Only |
Auth, POST requests |
Always fresh |
| Cache Only |
Precached app shell |
Immutable |
Install Prompt
let deferredPrompt: BeforeInstallPromptEvent | null = null;
window.addEventListener('beforeinstallprompt', (e) => {
e.preventDefault();
deferredPrompt = e;
showInstallButton();
});
async function installApp() {
if (!deferredPrompt) return;
deferredPrompt.prompt();
const { outcome } = await deferredPrompt.userChoice;
console.log(`Install ${outcome}`);
deferredPrompt = null;
}
Anti-Patterns
| Anti-Pattern |
Fix |
| Caching everything with Cache First |
Use Network First for dynamic data |
| No offline fallback page |
Precache an offline.html |
| No cache expiration |
Use ExpirationPlugin with maxEntries/maxAge |
| SW caches auth tokens |
Never cache sensitive data |
| No SW update strategy |
Use skipWaiting() + prompt user to refresh |
Production Checklist
Source: claude-dev-suite/claude-dev-suite — distributed by TomeVault.