Migrating from offlibrarySW()

From offlibrarySW() to Workbox

If your worker calls offlibrarySW() and you’re adopting Workbox, replace the one call with the Workbox pieces:

import { offlibrarySW } from 'offlibrary/sw';
offlibrarySW({ onComplete });
import { registerRoute } from 'workbox-routing';
import { NetworkOnly } from 'workbox-strategies';
import { initOfflibrary, offlibraryMatch, offlibraryHandler } from 'offlibrary/workbox';

initOfflibrary({ onComplete });
registerRoute(offlibraryMatch, offlibraryHandler({ fallback: new NetworkOnly() }));

What maps to what:

offlibrarySW() did	Now done by
Background Fetch events, notifications, page updates	initOfflibrary() (same options)
A fetch listener for stored files, with Range	registerRoute(offlibraryMatch, offlibraryHandler())
fetch(request) for misses	offlibraryHandler({ fallback }), any strategy

Nothing changes in the page, in IndexedDB or in the caches: already downloaded files keep working, and in-flight Background Fetches finish normally.

Keep calling initOfflibrary() (or offlibrarySW()) exactly once. Calling both, or offlibrarySW() with its default serve: true next to Workbox routes, adds a second fetch listener that answers stored URLs before Workbox sees them.

From hand-written Workbox glue (Offlibrary 0.1)

Offlibrary 0.1’s README suggested this:

import { registerRoute } from 'workbox-routing';
import { offlibrarySW, matchOfflibrary } from 'offlibrary/sw';

offlibrarySW({ serve: false });
registerRoute(({ request }) => request.destination === 'audio', async ({ request }) =>
  (await matchOfflibrary(request)) ?? fetch(request));

It still works. The 0.2 equivalent is shorter and covers more:

import { registerRoute } from 'workbox-routing';
import { NetworkOnly } from 'workbox-strategies';
import { initOfflibrary, offlibraryMatch, offlibraryHandler } from 'offlibrary/workbox';

initOfflibrary();
registerRoute(offlibraryMatch, offlibraryHandler({ fallback: new NetworkOnly() }));

• offlibraryMatch matches every stored URL (video, subtitles, tiles, models, not only audio), plus the cold-start cases.
• Misses go to a real Workbox strategy, with its plugins, instead of a bare fetch.
• initOfflibrary() names the intent; it’s the same as offlibrarySW({ serve: false }).

matchOfflibrary() and offlibrarySW({ serve: false }) remain supported for custom routing.