Andrea Giammarchi andrea.giammarchi at gmail.com
Mon Jan 13 08:23:36 PST 2014

Also true ... it's funny 'cause for ages we, developers, tried to make "ES3
classes" non enumerable so that for/in were not affected, we could extend
(avoiding conflicts, etc) and now that we could define such behavior as
default through a new ES6 class syntax we are "worried" that is not what
developers want ... I thought the fact basically every piece of code based
on `.hasOwnProperty()` check as first line of any `for/in` would be already
convincing nobody wants class enumerability and indeed I usually define
prototypes via defineProperties in a non enumerable way, but maybe I am the
only that never wanted/needed inherited enumerability for classes.

That being said the single/multiple mixin through prototype would be a
problem, if done pragmatically, but it can be easily solved with
`getOwnPropertyNames` ?

Make classes methods/properties enumerable by default ... I am still not
convinced is useful and I don't remember other OOP languages exposing
classes properties within loops.

Anyway, not a big deal, nothing to go nuts about ... we can all keep coding

Best Regards

On Mon, Jan 13, 2014 at 7:53 AM, Allen Wirfs-Brock <allen at wirfs-brock.com>wrote:

> On Jan 13, 2014, at 6:46 AM, Boris Zbarsky wrote:
> > On 1/12/14 11:57 PM, Andrea Giammarchi wrote:
> >> Recap: it seems we agree classes properties and methods should not show
> >> up in a for/in
> >
> > I should note that web developers commonly expect DOM methods/properties
> to show up in for/in (and in fact often write code depending on that,
> sometimes depending on the order of the enumeration).  So to the extent
> that we're trying to align DOM stuff with ES6 classes, we may need a
> class-level switch to decide whether a particular class has enumerable
> members or something.  :(
> Whatever the default enumerability, you can always change it using
> Object.defineProperty and you can write a utility function that will does.
> Define the utility as a method on function prototype and you can say
> something like:
> class Foo {};
> Foo.enumerableMethods();
> //or
> Foo.nonenumerableMethods();
> Allen
> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20140113/5466fbac/attachment.html>

More information about the es-discuss mailing list