Vaadin 14 offline demo?

Hi Guys,

Is there a demo project with vaadin 14 and offline capbilities? Specifically loading polymer templates?

As far as I’m aware, it’s similar to 10, but I’m getting javascript resource loading errors when I try to load components into the cache.

Refused to execute script from 'http://localhost:8080/frontend/boring-test.js' because its MIME type ('text/html') is not executable, and strict MIME type checking is enabled.

I’m trying to just load a simple H3 from a polymer template as a starting point for offline functionality - and wondering if there is any vaadin 14 related examples I could look at.