Suggestions for Set

Allen Wirfs-Brock allen at wirfs-brock.com
Wed Oct 3 09:06:52 PDT 2012


On Oct 3, 2012, at 7:47 AM, Erik Arvidsson wrote:

> On Wed, Oct 3, 2012 at 3:24 AM, Andreas Rossberg <rossberg at google.com> wrote:
>> On 3 October 2012 05:38, Brendan Eich <brendan at mozilla.com> wrote:
>>> Which is more important, iterating over holes (preserved if possible), or
>>> skipping them and therefore spreading array-likes but not iterables?
>> 
>> I, for one, couldn't care less about holes. We shouldn't compromise
>> any useful feature just for the sake of preserving some array hole
>> craziness.
> 
> Filling in holes with undefined seems like the right thing to do.
> People do not depend on holes.
> 
> Having Array.prototype. at iterator skip holes is bad because we don't
> have the index so we don't know that anything was skipped.
> 
> To repeat myself; holes are not common and we should keep things
> simple and having Array.prototype. at iterator iterate over array[0] to
> array[length - 1] is the most expected result.
> 


However, that would mean that Array.prototype.forEach and for-of over the same array are not always interchangeable.




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