PWA Offline Caching

Deelan uses a service worker for offline-first browsing after first load.

Files

• Service worker: public/service-worker.js
• Registration script: public/js/pwa-register.js
• Offline fallback page: public/offline.html

Caching Strategy

• Pre-cache on install:
  • /
  • /posts/
  • /snippets/
  • /offline.html
  • /js/filter.js
  • /js/search-core.js
  • /js/pwa-register.js
  • /mathjax/tex-mml-chtml.js
• Navigation requests: network-first with offline fallback page
• Static assets (/_astro/, /js/, /mathjax/): cache-first
• JSON requests: stale-while-revalidate
• Old caches are purged on activation based on cache version

Update Prompt Behavior

When a new service worker is installed and an older one is controlling the page:

1. The UI prompts the user to reload.
2. On confirmation, SKIP_WAITING is sent.
3. Page reloads on controllerchange.

Versioning

Cache version is set in public/service-worker.js:

• CACHE_VERSION = 'deelan-v2'

Bump this value when changing caching behavior/assets to force a clean cache upgrade.

Development Notes

Service workers can retain stale assets across local iterations.

To reset manually in browser devtools:

1. Application tab -> Service Workers -> Unregister
2. Application tab -> Storage -> Clear site data

Then reload the app.