Advanced Offline Caching Techniques for Progressive Web Apps

1. Introduction

Offline caching is a crucial aspect of Progressive Web Apps (PWAs) that allows applications to function seamlessly even without a network connection. This lesson will explore advanced caching techniques to enhance offline support.

2. Caching Strategies

3. Service Workers

Service workers act as a proxy between the web application and the network. They enable advanced caching techniques by intercepting network requests and serving cached responses.

Implementing a Service Worker

        // sw.js
        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);
                })
            );
        });
        

In the example above, the service worker caches essential files during installation and serves them during fetch events.

4. Best Practices

• Keep cache size reasonable.
• Implement cache versioning for updates.
• Regularly clear outdated cache entries.

5. FAQ