> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]>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
>>> [email protected]
>>> 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
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