[gruseom]

One of the stated reasons for Dart is that the V8 team was hitting a wall with making JS fast, beyond which a language with cleaner and more optimizable semantics is needed. I wonder, though, whether the nature of that wall has been clearly written up anywhere. I'd like to know if there are tricks in the category of "This would be annoying to write by hand in JS, but would be easy for a compiler targeting JS" that could be used to get around it.

Transcompilers that were target-specific could probably target server-side JS

I had an idea recently that (to me at least) is super exciting: someone should make a good language that compiles (à la Coffeescript/Parenscript) to JS but also to Lua. JS and Lua are close semantically, so it might not be so hard. (If it did turn out hard, it probably wouldn't be worth doing.) That would be a really interesting server-side alternative to both Dart (whose philosophy appears to be "run our VM on the server and compile to JS for the client") and Node.js.