for ... in loops currently iterate on only arrays; this should be revamped in favor of a more robust system, along the lines of this:
for element in expression do something
is evaluated something like
var iterator = expression[Symbol'iterator](), element;
while iterator.hasNext() do (element = iterator.next(); something)
for ... inloops currently iterate on only arrays; this should be revamped in favor of a more robust system, along the lines of this:is evaluated something like