They were pretty gung-ho about Ruby and Ruby on Rails between 2005 and 2010 or so. Then their hype moved to JavaScript and Node.js quite rapidly. It'll very likely move on to something else soon enough.
Lots of bad ideas. I mean, it is an ok feature, but by no means a killer-feature really. Ocsigen does the same thing: you can write your code in OCaml and the client-side part will by translated to JS automatically. Neat? Yes. Killer-feature? Probably not.
And JavaScript is really not that great to start with, so daveloping in something else server-side is not the worst idea.
And JavaScript is really not that great to start with
It's fine. IMO, all languages have warts you have to work around, once you know them it becomes a non-issue. I can't think of the last time one of those "JavaScript WTF" moments actually tripped me up in real code.
JavaScript is a convenience language across the stack for when the team is small, or even a single person.
The problem with web dev (I've thought about this a lot) is really that the browser is kindof the hinge. So no matter what you do for unifying languages, even porting modules so they're same on node front to back-end... you still can't really ever get to a point where you're unit testing pretty reliably through the full-stack.
So might as well test parts in isolation & who cares if there is one language throughout the whole stack as long as your devs are good at the languages required.
One day I think the impedance between server & client will disappear, but only when the browser's role as a rendering engine diminishes or finds better integration/intimacy with the codebase.
(and incidentally, i stopped caring so much about this struggle once i learned how to develop pretty reliable SOA. Haven't totally given up trying to conceptualize the perfect stack tho)
That's because there is a separate module for everything! Want to run "mkdir -p"? There is a module "mkdirp" just for doing that.
If you implemented every command as a separate library, of course there is going to be a lot of code out there.