> Le 30 mars 2015 à 10:46, Allen Wirfs-Brock <al...@wirfs-brock.com> a écrit :
>
>>
>> On Mar 30, 2015, at 10:12 AM, Axel Rauschmayer <a...@rauschma.de> wrote:
>>
>>>> It doesn’t seem that big of a deal, but one risk is: people mistaking a
>>>> class for a constructor, trying to subclass it as if it were a constructor
>>>> and things failing silently.
>>>>
>>> Can you give an example of what you mean?
>>
>> ```js
>> class MySuperClass {}
>>
>> // This function assumes that MySuperClass is an ES5 constructor function
>> function MySubConstructor(foo) {
>> MySuperClass.call(this);
>> this.foo = foo;
>> }
>> MySubConstructor.prototype = Object.create(MySuperClass.prototype);
>> MySubConstructor.prototype.constructor = MySubConstructor;
>> ```
>
> so if MySuperCall didn’t have the throw on [[Call]] behavior the above would
> work just fine.
>
> Allen
I see an issue when MySuperClass contains itself a super() invocation... at
least when that super-class is some builtin that doesn't support initialisation
of pre-allocated instances, like `Array`. As currently specified, it will just
throw, which is at least safe. It would be interesting to make it just work
without hacks such as `if (new.target) super(); else super.constructor(...);`,
and, in the same time, without silently break with `Array`, etc.
—Claude
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