Standard @iter module unfriendly to collection builders

Brendan Eich brendan at
Mon Nov 14 12:01:14 PST 2011

On Nov 14, 2011, at 11:59 AM, Erik Arvidsson wrote:

> On Mon, Nov 14, 2011 at 09:07, Allen Wirfs-Brock <allen at> wrote:
>> Another possibility would be to build in default @iterator methods on
>> Object.prototype and Array.prototype.  I'd probably make the object
>> implementation be an items for enumerable properties and the array
>> implementation iterate the values of 0..length-1 .
> Defining @iterator on Object.prototype seems like it would be a
> disservice to future js programmers. It would basically turn the
> for-of loop into another reflection based loop and we would be back to
> square one.
> I'm in favor of Array.prototype. at iterator though

Yes, good point! I forgot to say that in my last reply. That seems unproblematic since anything delegating to Array.prototype should be array-like in wanting for-of to iterate values in index order, skipping holes.


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