I downloaded prescript-halogen-6.1.3 and I tried to run the Ace example. When I open the index.html file I get a ReferenceError in the browser:
ReferenceError: Can't find variable: require

Comment by @natefaubion : It looks like the ace FFI previously relied on globals only, but was changed to use require, and I don’t think the halogen examples handle npm dependency bundling.

I got it working by using rollup for the npm dependency bundling. I had to manually install ace-builds.