On Sat, Dec 12, 2009 at 12:29 PM, Garrett Smith <[email protected]> wrote: > Object.prototype.propertyIsEnumerable does not consider properties in > the prototype chain. In effect, propertyIsEnumerable is a test to see > if an object has *own* property that is also enumerable.
At the end of < http://wiki.ecmascript.org/doku.php?id=conventions:isarraylike> I have added the issue: Unfortunately, the propertyIsEnumerable test above, despite the name, actually tests whether a property is both enumerable and own. This means the above predicate will reject objects that inherit a non-enumerable length property. I can think of no reliable and portable ES3R test which tests only property enumerability, except by running a for-in loop and testing the output. Doing so would kill the bounded-by-constant time virtue. Are we really this stuck? Can anyone think of a reliable, portable, and fast ES3R test that tests whether a property is enumerable, whether it is inherited or not? -- Cheers, --MarkM
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