On StackOverflow, scala.js has less than 1K questions in comparison to Scala as a whole which has around 90K. That’s more like 1%. Google trends shows Scala.js barely scratches 1% of the interest in Scala as a whole, which looks very close to the overall interest in Typescript (Scala.js’s direct competition?). JetBrain’s Survey’s may show higher usage percentage, but take in mind that this survey might very well introduce a selection bias (I for once didn’t even hear about it). I suspect this sort of selection bias was hurting Scala’s own survey, as I’ve noted in the past.
Fair enough, I admit not to know this project all that well.
Regardless, even if Scala.js does constitute 10% of Scala’s market-share, that’s not a strong enough reason in my opinion for pivoting the focus on JS developers, especially when Scala is heavily rooted in the Java world. And again, trying to cater for both JS and Java will prevent Scala from gaining popularity, as focusing on a single segment is of the essence.