For me, one of Scala's most important features is its type system, which you aren't able to get in JavaScript (I know about flow and TypeScript, but they don't even come close in terms of features).
I could have stopped reading after seeing your user name :)
Personally, Scala types are as powerful as intimidating, nevertheless acceptable for the value they enable for writers of libraries (which I probably never will be).
I read somewhere that Edward Kmett described how he writes apps: he first factors out the functionality into powerful, general-purpose libraries, and then just implements his app as a thin wrapper over the libraries. So, it's a matter of your mindset :-)