GoogleChrome/workbox ? reverse-engineered prompt

Build me a JavaScript toolkit for progressive web apps that makes offline support and service worker caching easy.

I want it to help web apps load faster, keep working when the connection is bad, and manage common caching patterns without a lot of boilerplate. Please set it up so the core pieces are reusable, the docs are clear, and there are a few examples or demos showing how someone would use it in a real app.

Make sure it feels polished, with good tests and sensible defaults, and keep it open source friendly. If you need to look up current best practices or browser docs while working, go ahead and do that. I’d also like the project to be organized so it’s easy to maintain and contribute to later.