There's quite a sizable fence you have to jump to get into progressive web app development. They have to serve over https, localStorage & service workers can be a pain, and there's a lot of fallbacks to implement for unsupported browsers (I'm looking at you, Safari!).
Then you can grade how progressive your app is by running https://github.com/GoogleChrome/lighthouse
Push notifications still aren't widely supported, sadly. https://developer.mozilla.org/en-US/docs/Web/API/Push_API
There's quite a sizable fence you have to jump to get into progressive web app development. They have to serve over https, localStorage & service workers can be a pain, and there's a lot of fallbacks to implement for unsupported browsers (I'm looking at you, Safari!).
There's also a great write-up on all that went into making pokedex.org http://www.pocketjavascript.com/blog/2015/11/23/introducing-...