Intellij handles Javascript great. One advantage of AppCode is that the IDE smarts aren't limited to Objective C code but also includes JS code, which works well when I'm working on my WebView/JS-based projects. I haven't used RubyMine directly, but I would be surprised if it didn't have JS smarts like all their other IDEs. However, I would echo chrizel's comment that Intellij would be that one IDE to rule them all, at least in your case. Intellij has some Ruby plugins that worked well enough when I played around with Ruby a few years back, and the plugin is developed and maintained by JetBrains themselves.