workbox-expiration

What is workbox-expiration?

The workbox-expiration package is part of the Workbox suite of libraries, which are designed to make it easier to build offline-first, service worker-powered web applications. The workbox-expiration plugin specifically manages the cache expiration and limits the number of entries in a cache.

What are workbox-expiration's main functionalities?

Cache Expiration

This feature allows you to set expiration parameters for cached responses. In the code sample, a cache-first strategy is used for requests to 'https://example.com', with a maximum of 60 entries and a maximum age of 30 days before the cached entries are purged.

workbox.routing.registerRoute(
  ({url}) => url.origin === 'https://example.com',
  new workbox.strategies.CacheFirst({
    cacheName: 'images',
    plugins: [
      new workbox.expiration.ExpirationPlugin({
        maxEntries: 60,
        maxAgeSeconds: 30 * 24 * 60 * 60, // 30 Days
      }),
    ],
  }),
);

Cache Entry Limit

This feature limits the number of entries in a cache. In the code sample, a stale-while-revalidate strategy is used for requests to 'https://example.com', with a maximum of 50 entries in the 'articles' cache.

workbox.routing.registerRoute(
  ({url}) => url.origin === 'https://example.com',
  new workbox.strategies.StaleWhileRevalidate({
    cacheName: 'articles',
    plugins: [
      new workbox.expiration.ExpirationPlugin({
        maxEntries: 50,
      }),
    ],
  }),
);

Purge on Quota Error

This feature automatically purges caches if the browser's storage quota is exceeded. In the code sample, a network-first strategy is used for requests to 'https://example.com', with the 'purgeOnQuotaError' option set to true.

workbox.routing.registerRoute(
  ({url}) => url.origin === 'https://example.com',
  new workbox.strategies.NetworkFirst({
    cacheName: 'documents',
    plugins: [
      new workbox.expiration.ExpirationPlugin({
        purgeOnQuotaError: true, // Automatically delete caches if quota is exceeded
      }),
    ],
  }),
);

Other packages similar to workbox-expiration

sw-toolbox

sw-toolbox is a legacy library for service worker caching strategies and was a precursor to Workbox. It offers similar functionalities for caching and managing cache expiration. However, Workbox is recommended over sw-toolbox as it is more modern and actively maintained.

sw-precache

sw-precache is another legacy Google library that generates a service worker script that precaches resources. It includes some cache management features but is less flexible and modular compared to workbox-expiration. Workbox has since superseded sw-precache.

sw-cache-expiration

sw-cache-expiration is a standalone library for managing cache expiration in service workers. It provides similar functionality to workbox-expiration but is not as widely adopted or supported as Workbox, which is a comprehensive suite of tools for offline caching.

README

This module's documentation can be found at https://developers.google.com/web/tools/workbox/modules/workbox-expiration