Re: Iterating over the properties of an ECMAScript object

On Friday, April 18, 2014, Brian Birtles <bbirtles@mozilla.com> wrote:

> Hi Rick,
>
> Thank you very much for your mail.
>
> (2014/04/18 3:08), Rick Waldron wrote:
> > ...
>
>> Agreed, and a step further would be to specify that only valid
>> properties are recognized. Here's a naive hack to illustrate:
>>
>
> I might have misunderstood this point.
>
> The algorithm in 5.15.2[1] begins by creating a list of supported property
> names and only calling [[Get]] on properties in the input object whose
> property name is in the list of supported property names.
>
> It still iterates over the list of properties in the input object (not the
> list of supported property names) for performance reasons: in the common
> case, the input object only has one or two properties whilst the list of
> supported property names is long and is expected to grow over time.
>
> Does that match what you had in mind?
>
>
Indeed, sorry for the noise—I completely missed that.

Rick

> Thanks again,
>
> Brian
>
> [1] http://dev.w3.org/fxtf/web-animations/#processing-a-keyframe-object
> (Unfortunately, named anchors don't currently work very well but it's
> section 5.15.2, Processing a Keyframe object)
>