One thing that could be improved/fixed is that XCode console handling fails to do a sprintf on its input :
console.log("Just fetched %s-item from endpoint=%o", itemCount, endpoint);
Does output "Just fetched %s-item from endpoint=%o" in XCode while it could probably have the sprintf :
"Just fetched 12-item from endpoint=[Object]"
Not perfect but could be really useful for non-scalar vars.