When using Scala.js or Scala Native, make sure your dependencies are specified using %%%, for
example
// Works for JVM, Scala.js and Scala Native
libraryDependencies += "org.scodec" %%% "scodec-bits" % "1.1.32"
Whereas in JVM projects you would see dependencies specified with %%:
// JVM ONLY!
libraryDependencies += "org.scodec" %% "scodec-bits" % "1.1.32"
Hot tip: if you have Scala.js or Scala Native in any of your SBT modules, you can use %%%
for every dependency. This way both JVM and SJS/SN dependencies will work perfectly.