[Server Workers can be used to make web apps offline-capable](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Offline_Service_workers). [WorkBox can be used to do this](https://developers.google.com/web/tools/workbox/guides/get-started#offline_fallback).
Server Workers can be used to make web apps offline-capable.
WorkBox can be used to do this.