Originally Posted by liorean
why are you using the for..in loop on an array instead of a plain for loop with a numeric iterator variable?
it was just an example - having said that, it's not that out of the realm of feasibility - i'll often construct arrays as hash tables to use both associative and integer access - the added weight of array methods is neglible.
as regards the original question -
flash's proprietary actionscript has a method (ASSetPropFlags) that allows you to prototype core classes at will and hide whatever bits and pieces you wish from iteration. i had hoped for something similiar or a setter to the getter of isPropertyEnumerable.