TIL that you can run frontend Javascript with a package like Deno. I thought you need a proper headless browser for it.

I was thinking the same walking into this thread. I figured DOM/CSS/HTML would be part of the black box magic, but I suppose from the perspective of JS all of that can be faked appropriately.

I think you only need something like `jsdom` to have the core API available. The DOM itself is just a tree structure with special nodes. Most APIs are optional and you can provide stubs if you're targeting a specific websites. It's not POSIX level.