I think Closure Compiler is a lot more useful than this. You get type checking, but you also get best of breed optimization/minification too. You don't get the

I think Closure Compiler is a lot more useful than this. You get type checking, but you also get best of breed optimization/minification too. You don't get the automatic runtime test generation stuff, but that's more along the lines of an add-on utility like Quickcheck/Scalacheck.