I doubt there is lots of JS code in NPM which is independent of either Node or browser APIs when including transitive dependencies. But that is besides the point. I said no NPM as in no access to NPM. Not just no node APIs. Let's say you install a library from npm using either npm or yarn. Its downloaded into the node_modules directory. how would you require it as an es6 module?

Another poor design from the GNOME team. How is the JS code in the gnome extension distributed? It is embedded in .so files! so much for hackability. (I learned this when upon a fresh Ubuntu install I run into bug in my gnome shell version which was a one liner fix but I couldn't find the file in the backtrace.)