[jducoeur]

I think you're misreading the situation. Scala.js sits on top of Javascript, and leverages everything in the JS ecosystem. Interoperability is central to the Scala.js story.

For example, I'm building a product with a moderately complex front end. I'm using about 10-15 JS libraries, including JQuery and JQuery UI, as part of that. I just write a strongly-typed facade on top of each library, describing what it does (which takes just a few minutes), and I'm off to the races. Similarly, other folks are doing things like writing Scala.js adapters for React, Angular, and so on.

So Scala.js isn't in competition with the existing JS libraries. Far from it: I think of it as a much better way to use the Javascript resources that already exist...