Java script code
Your code looks fine to me.
Maybe this is a bug in Aether/Esper? @nick @rob
Does it work if you explicitly turn Esper off? http://codecombat.com/play/level/friend-and-foe?esper=false
Yes, it working. No error in: http://codecombat.com/play/level/friend-and-foe?esper=false