Usage of Scala.js is steadily growing. Several indicators suggest that 1 in 5 Scala developers use Scala.js at this point. It's regularly brought up as one of the strongest suits of Scala.
Usage of Scala itself is less shiny if you look at market share. But I believe it's still growing in absolute numbers, only quite slowly.
>Usage of Scala.js is steadily growing. Several indicators suggest that 1 in 5 Scala developers use Scala.js at this point.
Wow! 4 out of 20 total ain't bad!
Jocking aside the starting set (Scala developers) is already small, so it's not like either it or even less Scala.js is going to be a major player anytime soon.