On Sep 27, 2013, at 9:44 PM, Kevin Smith wrote:
>
>
> All the noise we made about Object.extend was unclear? From jQuery:
>
> https://github.com/jquery/jquery/blob/master/src/core.js#L157
>
> Many similar functions, going back to Prototype's Object.extend:
>
> Object.extend = function(destination, source) {
> for (var property in source)
> destination[property] = source[property];
> return destination;
> };
>
> Thanks. I believe this supports my position. Regardless of how @iterator is
> defined, consider this:
>
> extendObject(target, someObjectWithIterator);
>
> If `someObjectWithIterator` has an @iterator method (be it string or symbol
> keyed), I would expect that after this statement runs, `target` would also
> have that @iterator method. To write it a different way:
>
> extendObject(target, {
> "@iterator"() {}
> });
>
> Or:
>
> extendObject(target, {
> [Symbol.iterator]() {}
> });
>
> Either way I would be surprised if the "iterator" function was **not**
> copied. I think this example argues for enumerability, at least in some
> cases. Or equivalently, not all meta-level hooks appear to want
> non-enumerability.
>
> { Kevin }
Note that ES6 provides two built-in functions that provide Object.extend-like
functionality. One that uses enumerability and assignment semantics and one
that ignores enumerability and uses property definition semantics:
Object.assign
http://people.mozilla.org/~jorendorff/es6-draft.html#sec-19.1.3.1
Object.mixin
http://people.mozilla.org/~jorendorff/es6-draft.html#sec-19.1.3.15
When people start using those, they will be expressing an implicit intent.
It is for legacy libraries such as jquery Object.extend where the intent
regarding meta=level properties is unclear.
Allens
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