It's ultimately just a little event listener function that accepts a Request object and returns a Response object. I bundled the service worker by running a quick `npx esbuild --minify --bundle --outfile=sw.js sw.ts` command, and it produced an 18.6kb JS file in 10 milliseconds. That's not even half the size of libraries like HTMX, Alpine, and jQuery.

You can of course use the CacheStorage API directly as well (you're not obligated to use a mock server): https://developer.mozilla.org/en-US/docs/Web/API/CacheStorag...

I've certainly seen crazier things though. People routinely include entire copies of Ubuntu LTS in their Docker images to ship tiny HTTP servers.