Le 18/02/2014 18:55, Erik Arvidsson a écrit :
> https://bugs.ecmascript.org/show_bug.cgi?id=2511
>
> We now have our first setter in the spec. However, it is speced to 
> return the value itself. This is pretty inconsistent with WebIDL and 
> the common practice to not include a return value in setters in object 
> literals.
In practice, the returned value of setting is the value on the rhs of the =.

     var o = {set b(v){return 12;}} // this return statement is useless

     console.log(o.a = 13); // 13
     console.log(o.b = 14); // 14

It might be useful to return a different value on setting. I think Haxe 
does it.
Note that it would require to rework the set trap of proxies a bit 
(currently, it returns a boolean indicating success or failure).

> Can we get the spec changed to return undefined?
That would be the most coherent option with the language as it is today.

David

In practice, the returned value of setting is the value on the rhs of the =.

     var o = {set b(v){return 12;}} // this return statement is useless

     console.log(o.a = 13); // 13
     console.log(o.b = 14); // 14

It might be useful to return a different value on setting. I think Haxe 
does it.
Note that it would require to rework the set trap of proxies a bit 
(currently, it returns a boolean indicating success or failure).

> Can we get the spec changed to return undefined?

That would be the most coherent option with the language as it is today.