If you’re looking at some material to learn PWA (Progressive Web App) there is a video course I don’t want to miss.
The course is available on YouTube under “PWA Tutorial for beginners” by The Net Ninja and is really well done.
The course shows step by step how to create your first PWA so it is recognized by Chrome and installed like an app on Android phones (PWA support on iOS is still limited).
It shows how to use the cache to make your webapp works offline, how to setup the service worker (that is the really new concept on the web technology) and how to manage the lifecycle of that object.
There is even a part with example on how to leverage the Firebase Google service to give more power to your webapp (and to avoid to have a personal deployment server).
Note: I’m not affiliated with The Net Ninja, only enthusiast of those video lessons.