Your main point appears to be sharing code on the client and server side. Scala.js has reached 0.1 and is quite decent [1]. Personally, the only code I find wor

Your main point appears to be sharing code on the client and server side. Scala.js has reached 0.1 and is quite decent [1]. Personally, the only code I find worth sharing is validation code and template rendering code. As for "maintainability", I find it is much lower in node.js and JS projects in general. Each has its own structure and is scary to refactor (unless you're a TypeScripter or something). I don't believe it's fair to use those two points to say it "demolishes" Scala/Play. Also, some webapps do real work per request (not just routing IO), and even though it is very quick (i.e. not worth farming out to a resque-like job engine or a web-worker in node), the fact that it blocks the node process scares me as well. 1 - http://www.scala-lang.org/news/2013/11/29/announcing-scala-js-v0.1.html http://www.scala-lang.org/news/2013/11/29/announcing-scala-j...