scalacss

While a bit rough around the edges, the full type safe server-client stack can be done in Scala with Play[0] + Scala.js[1] + ScalaCSS[2] I say rough because despite Scala.js' fantastic performance characteristics, you're looking at 100kb file size off the bat; from there generated code size is reasonable, but that's a pretty big hit, particularly for cache challenged mobile clients. Otherwise, being able to tie Play's type safe reverse routing into the client is a big win. Previously with GruntJS + Coffeescript approach I'd get small file size, but complete lack of safety; just winging it with `routes.user.maybeNotExist(id)`. [0] https://github.com/playframework/playframework/ [1] https://github.com/scala-js/scala-js [2] https://github.com/japgolly/scalacss

While mentioning other tech, I have found Scala.js with Scala.Rx [1], ScalaTags [2], and some glue [3] a great way to actually do reactive DOM updates based on state change. I find this way cleaner than building and diffing entire DOM trees (even if they are just AST's in JS). Mixed with ScalaCSS [4] you have a nice type safe solution. 1 - https://github.com/lihaoyi/scala.rx 2 - https://github.com/lihaoyi/scalatags 3 - https://github.com/rtimush/scalatags-rx 4 - https://github.com/japgolly/scalacss/