Back in 2005 at Bloomberg we decided to move all Terminal app development to server-side JS, using a homegrown system built on top of a custom GObject (GObjectIntrospection didn't exist at the time, so we made our own) and SpiderMonkey. IIRC, GNOME was starting to experiment with JS around the same time. JS isn't for everyone, but it certainly makes app development faster than writing apps in C/C++.