Added to my Learn2JS project, and it's fairly usable now for rapid development, I can move over the application logic of little tools and they just show up in the catalog and work. Still no live editor, you have to drop a script in lib or a user dir, but it's getting closer to instant-on coding!
Try it out, then look at the scripts, alien
is just block sprites but it's a decently hard shooter (there's some oddness about hit detection, and it needs upgrade drops to be a real game). maze
is the usual maze generator; drawing text right now because I haven't hooked up the sprite graphics. Both are about as close to minimal code needed for the task as you can get.