[maybeOneDay]

This may be a noob question - how do you go about filling in the other side of that abstraction in the JS (presumably) post transpilation? Is it just that you had a set of files in JS developed separately and the build/deployment system could inject those files in specific expected areas?

[timmg]

Yes, you have it exactly right. We basically had three different hand-coded implementations of the same classes, each in a different language.