Re: undefined values in dictionaries

On Tue, Jun 11, 2013 at 1:43 PM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
> Consider this IDL:
>
>  dictionary Foo {
>    DOMString member = "something";
>  };
>
> and the following object being passed to an argument taking Foo:
>
>   { member: undefined }
>
> Per current WebIDL, this will be treated identically to { member:
> "undefined" }.  Is that what we want, or should it be treated identically to
> { } (which is treated like { member: "something" } in this case) instead?
>
> Or put another way, for dictionaries the current "member is present"
> indicator is what "member in dictionary" returns, not what
> "dictionary.member != undefined" returns.  Both seem valid options depending
> on the API contract...

I think there's agreement here that we should test "dictionary.member
!= undefined" rather than "member in dictionary". This aligns with how
dictionary handling is handled by ES6. The WebIDL spec just hasn't
been updated yet.

/ Jonas