typeof symbol (Was: Sept 19 TC39 Meeting Notes)

Rick Waldron waldron.rick at gmail.com
Mon Oct 1 13:48:53 PDT 2012


On Mon, Oct 1, 2012 at 4:23 PM, David Bruant <bruant.d at gmail.com> wrote:

> Le 01/10/2012 21:42, Brendan Eich a écrit :
> > Andreas Rossberg wrote:
> >> On 30 September 2012 00:08, Brendan Eich<brendan at mozilla.org>  wrote:
> >>> I think this is too philosophical a discussion to result in a strong
> >>> reason
> >>> to risk "symbol". Just my gut-check. Other TC39ers should weigh in
> >>> (Andreas
> >>> R. especially).
> >>
> >> Type "symbol" would be my preference, but it is difficult to estimate
> >> (for me) whether that involves a risk.
> >>
> >> However, this clearly is an issue beyond symbols alone. The same
> >> problem re-arises whenever we have to add new primitive types in the
> >> future. It doesn't seem like a sustainable strategy to fake any new
> >> type ever into an object. Perhaps it is less harmful on the long run
> >> if we took the chance to clarify _now_ that the set of strings
> >> returned by 'typeof' is not fixed, and should not be treated as such?
> >
> > I could go for that (see my "int64" and "uint64" argument).
> >
> > And as noted, IE has softened up the developers, or so I hear.
> >
> > Someone who knows more should weigh in. I even heard that in IE
> > JScript (or possibly even IE9/10 Chakra -- "JavaScript"), typeof can
> > return "unknown"! True?
> Try "typeof document.createElement('div').offsetParent" on IE6-8. I
> can't verify because I'm not Ubuntu right now, but if I recall it will
> give you "unknown".
> If it works, credit where it's due, John-David Dalton shared this to me
> a while ago. If it doesn't work, sorry for the noise.
> If I had to guess, I'd say it's been fixed in IE9, but I'm interested if
> someone can test.
>
>
I don't need to run it to confirm. It definitely "unknown" ;)



>  David
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