domenic at domenicdenicola.com (2013-07-23T17:37:51.298Z)
> That's unpleasant. [...] Much old code will break.
Indeed. I hadn't actually noticed that change until just now. It looks
like ES6 code can take advantage of `Object.isObject()`, which seems to
delegate the work to Type(*x*) [1]. It wasn't overwhelmingly clear to me,
but I would assume `Object.isObject('foo') === false` and
`Object.isObject(new String('foo')) === true`.
Has anyone surveyed/looked into what the fallout of throwing on stuff like
`Object(undefined)` will be?
[1]: http://people.mozilla.org/~jorendorff/es6-draft.html#sec
> That's unpleasant. [...] Much old code will break. Indeed. I hadn't actually noticed that change until just now. It looks like ES6 code can take advantage of Object.isObject(), which seems to delegate the work to Type(*x*) [1]. It wasn't overwhelmingly clear to me, but I would assume `Object.isObject('foo') === false` and `Object.isObject(new String('foo')) === true`. Has anyone surveyed/looked into what the fallout of throwing on stuff like `Object(undefined)` will be? [1] http://people.mozilla.org/~jorendorff/es6-draft.html#sec-8 On Mon, Jul 15, 2013 at 11:09 AM, Mark S. Miller <erights at google.com> wrote: > I see. That's unpleasant. In ES5, Object(x) can never throw, and so the > code paths using |x === Object(x)| are not prepared for a throw. Much old > code will break. > > > On Mon, Jul 15, 2013 at 8:01 AM, Jeremy Martin <jmar777 at gmail.com> wrote: > >> > s === Object(s) >> >> This should throw a TypeError. In the case of a Symbol, `Object(*value*)` >> results in `ToObject(*value*)` [1]. And, in the case of Symbol, >> ToObject should throw a TypeError [2]. >> >> [1] http://people.mozilla.org/~jorendorff/es6-draft.html#sec-15.2.1.1 >> [2] http://people.mozilla.org/~jorendorff/es6-draft.html#sec-9.1.9 >> >> On Mon, Jul 15, 2013 at 10:48 AM, Mark S. Miller <erights at google.com>wrote: >> >>> Given that s is a Symbol and b is a Bignum, is >>> >>> s === Object(s) >>> >>> ? >>> >>> Is >>> >>> b === Object(b) >>> >>> ? >>> >>> The reason I ask is that x === Object(x) is often used to distinguish >>> primitive values from objects. The other thing that's often used is typeof, >>> but these uses of typeof usually assume that the full range of possible >>> answers is already known. If we're going to be expanding the typeof >>> answers, then we need guidance on how to write this test now (es5) such >>> that it stays robust. >>> >>> >>> -- >>> Cheers, >>> --MarkM >>> >>> _______________________________________________ >>> es-discuss mailing list >>> es-discuss at mozilla.org >>> https://mail.mozilla.org/listinfo/es-discuss >>> >>> >> >> >> -- >> Jeremy Martin >> 661.312.3853 >> http://devsmash.com >> @jmar777 >> > > > > -- > Cheers, > --MarkM > -- Jeremy Martin 661.312.3853 http://devsmash.com @jmar777 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20130715/df092edb/attachment.html>