On Mon, Oct 21, 2013 at 11:26 PM, Andrea Giammarchi <
[email protected]> wrote:
> As sanity/integrity check, `Object.assign` should be something like this
> to me ...
>
> ```javascript
>
> for (var property in source) {
> if (Object.prototype.hasOwnProperty.call(source, key)) {
> if (key in target) {
> Object.defineProperty(
> target, key,
> Object.getOwnPropertyDescriptor(
> source, key
> )
> );
> } else {
> target[key] = source[key];
> }
>
This is exactly why there is Object.assign and Object.mixin (originally
called Object.define), because you can't make this semantic decision and
assume that it's what all code wants all the time.
> }
> }
>
> ```
>
Traceur has:
function assign(target, source) {
var props = $getOwnPropertyNames(source);
var p, length = props.length;
for (p = 0; p < length; p++) {
target[props[p]] = source[props[p]];
}
return target;
}
Which is correct.
> If this is what every dev should do in order to have a meaningful version
> of current `Object.assign`,
>
But it's wrong.
> I agree with Rick that in core this could/would be properly optimized and
> made faster.
>
Thanks
Rick
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