Determine if a value is Callable/Constructible

Axel Rauschmayer axel at
Mon Mar 30 13:34:57 UTC 2015

> > Don’t the different assumptions as to where the instance is allocated ever clash here? What if `MySuperClass` were:
> >
> > ```js
> > class MySuperClass extends Error {
> > }
> > ```

> MySubClass preallocates when invoked via new. Just like ES5. So, `````` is same as ES5.  What happens in MySuperClass depends upon the ES6 level programmer.

Right, but I don’t see how an ES5-style constructor MySubContructor can allocate its instance and then have it initialized by an ES6 class (where the instance is allocated by a super-class). This is about ES5 code being confronted with ES6 code and assuming to see a constructor.

Dr. Axel Rauschmayer
axel at

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