Comment by WorldMaker

It does sound a lot like what Progressive Web Apps (PWAs) are supposed to be. It's very close to how the original Manifest.json worked when given an html/js/css/assets list.

Only a couple of browsers supported that version of Manifest.json. Chrome developers thought it was too much of an 80/20 solution and decided to get deep in the weeds of the 20% instead of delivering the 80% solution while they worked. That's what got us the way too low level and hard to reason with Service Worker APIs for PWAs. It's over-engineered for the 20% of use cases in a way that makes "easy" 80% so much harder than it ever should have been. Chrome developers still randomly promise the web that the "easy high level API" will arrive any day now, but looking at the mess that is Workbox (their team's supposed-to-be high level building block library for Service Worker PWA APIs) it still doesn't look like it will happen any time soon.

It's more the shame because we briefly had a simple JSON manifest format for assets. That JSON format should have been easy to emulate in the Service Worker APIs if those APIs truly were meant to solve the problem, not just solving more interesting problems in a related space that a minority of use cases needed. Google doesn't currently have enough incentive to make PWAs easy to build, and as long as Chrome is the majority browser, Google is the major obstacle.