typeof operator and platform objects

[TimothyGu]

The typeof operator is defined for "Object (non-standard exotic and does not implement [[Call]])" to return "Implementation-defined. Must not be "undefined", "boolean", "function", "number", "symbol", or "string"."

From

The semantics of the essential internal methods for ordinary objects and standard exotic objects are specified in clause 9.

it seems that "non-standard" means "non-ECMA-262". Then named property objects, legacy platform objects, etc. are all non-standard. We should say in Web IDL that they should all return "object"

[bzbarsky]

We should say in Web IDL that they should all return "object"

Sort of. HTMLAllCollection needs to return "undefined". Which the ES spec doesn't allow, of course.

[bzbarsky]

But yes, for the rest we should spec that they return "object"

[TimothyGu]

Which the ES spec doesn't allow, of course.

Now it does :)

See https://tc39.github.io/ecma262/#sec-IsHTMLDDA-internal-slot-typeof and whatwg/html#3087.

[bzbarsky]

Now it does :)

Oh, a COMEFROM spec. Lovely. ;)

[annevk]

I actually think ES shouldn't say this is implementation-defined. It should be host-defined and there should be a hook for hosts to make it work more automatically. And perhaps given that document.all is fixed there need not be host exceptions?

[littledan]

Good point; I filed tc39/ecma262#1440 to discuss a simplification here.