Have there been any performance improvements under Firefox? Almost every Elm demo that I've seen so far has been basically unusable under that browser. I've been told that the issue is some difference between Chrome and FF with canvas drawing... but regardless of where the fault lies, Elm is pretty much a Chrome-only technology until that gets worked out.
Author of that PR here. It may help Firefox some, but in my experiments I'm still seeing that driving canvas animations with Elm performs much better in Chrome than in Firefox.
If there are any Firefox engineers reading this, maybe there is a good benchmark to be extracted out of this observation? I'd be interested in discussing this with someone. Feel free to reach out at the e-mail address in my profile.