It's a bit late for an announcement, since we actually published this a couple of weeks ago, but Google's Cordova team has built a Service Worker plugin for iOS Cordova apps.
It's npm-published exclusively, so you can finally install this without cloning the repo, so maybe that makes this a good time to publicize it ;) This means that you can use all of the Service Worker APIs (Cache, Fetch, etc) that you would use to make an offline web app -- including updating your app assets from the network -- and build a Cordova app the same way. The plugin is an extendable platform, as well, so we hope to publish some other APIs on top of it (geofencing, push, background sync) fairly soon. https://www.npmjs.com/package/cordova-plugin-service-worker
