Must built-in prototypes also be valid instances? (Was: Why DataView.prototype object's [[Class]] is "Object"?)

Oliver Hunt oliver at
Mon Oct 1 08:11:03 PDT 2012

> V8 says no to both. And I fail to see what benefit there is to
> separating the two. In fact, it seems hostile to programmers to do so.
> I think Allen is absolutely right that the magic incest of current
> built-ins is not going to scale, is semantically questionable, and
> should best be abandoned.

Agreed, the pattern of FooPrototype being an instance of Foo makes things more complicated for no obvious reason, and is only really used by conformance suites anyway :D

I see no reason ever create a new type that has screwy prototype/instance magic, the existing cases only get in by virtue of dubious backwards compatibility claims.


More information about the es-discuss mailing list