[hellofunk]

I have to agree that it is much more likely the code was not written well or idiomatically if there were performance problems. Still, I'd be very surprised that the problems actually were there.

And I actually test my clojurscript lines that I write in a JVM repl! Semantics between the two languages are virtually identical, I can test out my ideas for the JS target in a Java environment. Perhaps the OP has a different definition of "semantics".