Service Worker Caching Techniques

Introduction

Service Workers are scripts that run in the background of a web application, allowing for features like offline support and caching strategies to enhance user experience.

Key Concepts

• Service Worker: A script that intercepts network requests and can manage cache.
• Cache Storage API: A storage mechanism that allows you to store and retrieve requests and responses.
• Fetch Event: An event triggered whenever a network request is made, which can be intercepted by the service worker.

Caching Strategies

1. Cache First: Check the cache first, and fetch from the network if not found.
2. Network First: Try to fetch from the network first, and fallback to the cache if offline.
3. Stale While Revalidate: Serve the cached content while updating the cache in the background.

Code Example

self.addEventListener('install', (event) => {
    event.waitUntil(
        caches.open('my-cache').then((cache) => {
            return cache.addAll([
                '/',
                '/index.html',
                '/styles.css',
                '/script.js'
            ]);
        })
    );
});

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

Best Practices

• Use versioning for your caches.
• Regularly clean up old caches.
• Test your service worker in various scenarios (online/offline).

FAQ

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