While this would be awesome to have here at Laracasts. It's an enormous undertaking for Jeffery to understand everything about Progressive Web Apps as the scope of this site is more about Laravel sprinkled with some related technologies. Making API requests has been covered here pretty well IMO. So if you're interested in learning more, there are free resources around the web that explains it pretty well. I would start with a checklist for PWA, try to have that completed, and then see where in the road map does Laravel fit and find solutions derived from many lessons already available.
Google already provides, starter template, with Service Worker, and etc. I would modify it by removing any design/solution concept ex. Weather App, strip it to the bone, and build on top of that.
Hope that helps, best Alen.