Service Worker Performance Tuning

1. Introduction

Service workers act as a proxy between web applications and the network, enabling features like offline access, background sync, and push notifications. Proper performance tuning of service workers is crucial for optimizing load times and enhancing user experience in Progressive Web Apps (PWAs).

2. Key Concepts

• Service Worker Lifecycle: Understanding the phases (install, activate, fetch).
• Caching: Storing assets to minimize network requests.
• Fetch Event: Intercepting network requests to serve cached content.

3. Caching Strategies

Implementing effective caching strategies significantly improves performance. Here are several options:

1. Cache First: Serve content from cache; if not available, fetch from network.
2. Network First: Try fetching from the network; fall back to cache if it fails.
3. Stale While Revalidate: Serve cached content immediately, while updating cache in the background.

4. Network Management

Manage network requests intelligently to enhance performance:

self.addEventListener('fetch', event => {
    event.respondWith(
        caches.match(event.request).then(cachedResponse => {
            return cachedResponse || fetch(event.request);
        })
    );
});
        

5. Best Practices

• Keep service worker scripts small and efficient.
• Use skipWaiting() to activate new service workers immediately.
• Limit the number of cache entries to prevent stale data.
• Implement cache versioning for easy updates.
• Test service workers thoroughly across different browsers.

6. FAQ

if ('serviceWorker' in navigator) {
    navigator.serviceWorker.register('/service-worker.js')
    .then(registration => {
        console.log('Service Worker registered with scope:', registration.scope);
    }).catch(error => {
        console.error('Service Worker registration failed:', error);
    });
}