Very, actually. It's about time I add more tests, maybe remove its opinion about what view context to dump to JavaScript (leave that to the end dev), and version it as 1.0. I think it's had one significant bug in almost a year and no problem issues in the past 6 months.
Ha, so mere days after I told you it's stable I had to ship a fix to make sure that it was serving precompiled assets when they are available. We had never noticed because our server-side assets had never gotten large enough to go over Heroku's 60-second boot time limit. So anyway, if you're trying this out, please upgrade execjs-rails now. We cut our app's production boot time by roughly 80% by doing so.