Le 18/03/2011 18:00, Oliver Hunt a écrit :
> I kind of dislike the proliferation of .create methods. It's seems
> inelegant. What if we had (use __proto__ for semantic description)
>
> Object.subclass = function(constructor) {
> "use strict";
> function cons() {
> var result = constructor.apply(this, arguments);
> result.__proto__ = cons.prototype;
> return result;
> }
> cons.prototype = Object.create(constructor.prototype);
> return cons;
> }
>
> This would provide a function that does that allows arbitrary "subclassing"
> of any function. Obviously there are issues (call vs. construct behaviour,
> etc), but I think it's not too far off being a decent generic solution.
After giving it further thought, I think that this is a good idea, but
the syntax is wrong.
You'll probably agree that the constructor argument needs a
[[Constructor]] internal method, but your function would need to filter
out things given as arguments which don't. To better target "things that
have a [[Constructor]] internal method", I would add something to
Function.prototype (as it is done with the
Function.prototype.createDelegatingTo idea). So I would go more for
something like:
Function.prototype.subclass = function() {
function cons() {
var result = new this; // throws if this doesn't have an
internal [[Construct]]
result.__proto__ = cons.prototype;
return result;
}
cons.prototype = Object.create(this.prototype);
return cons.bind(this);
}
This also addresses the issue you raise "(call vs. construct behaviour)".
David
_______________________________________________
es-discuss mailing list
[email protected]
https://mail.mozilla.org/listinfo/es-discuss
