The problem#
Java and JavaScript are insufficiently easily confused.
I had some code I wanted to run on the user's computer and not the
server, and it specifically had to be in Java to reference a library
written in Java. I found1 Doppio, a JVM written in
TypeScript, but it had bitrotted enough that I was having
trouble getting it to run, despite confirming it did what I wanted
using the official demo, which provides an in-browser
console-like interface.
The solution#
I was able to piece together a working simple page using Doppio, modified from the official example. It's in a repository on GitHub and should be straightforward to modify for your needs.