> Also, why not create multiple scala-Js projects to do what you're looking to do?

That won't help. Scala.js banks heavily on whole program optimization to reduce the size of emitted Javascript. Two independent Scala.js modules will contain redundant code including likely upwards of 100kb of Scala standard library (collections, futures, etc.)

There is an issue about webpack-style code splitting support for Scala.js somewhere on github, and Sebastien said it's doable with the current architecture, so we'll likely get that eventually, but it's not there yet.

I do love working with Scala.js - great language and great interop with JS.