(x) => {foo: bar}

[Marius Gundersen]

One scenario where arrow functions are likely to return objects is in the
map function of arrays and the pipe function for streams. For example:

[1,2,3]
.map(x => {value: x,  double:2*x})
.filter(x => x.double < 5)

Marius Gundersen

On 5 Jan 2015 21:16, "Kevin Smith" <zenparsing at gmail.com> wrote:
>
> Also, I did some analysis on this issue way back when.  In the codebases
that I looked at the percentage of "bound this functions" which simply
returned an object literal were quite low.
>
> (See the "%Object Literals" column)
>
>
https://docs.google.com/spreadsheet/ccc?key=0Aro5yQ2fa01xdENxUzBuNXczb21vUWVUX0tyVmNKTUE#gid=0
>
https://docs.google.com/spreadsheet/ccc?key=0Aro5yQ2fa01xdEJySWxhZ1VoZ0VaWTdldXp4NUtJd3c#gid=0
>
> (from https://esdiscuss.org/topic/btf-measurements)
>
> Of course, actually having arrow functions will change the situation to
some degree, but the current tradeoff made sense in light of that evidence.
>
>
> On Mon, Jan 5, 2015 at 3:06 PM, Brendan Eich <brendan at mozilla.org> wrote:
>>
>> Kevin Smith wrote:
>>>
>>>
>>>     I think hacking around this would not get rid of the footgun, but
>>>     would just make it more complicated to understand the footgun,
>>>     personally.
>>>
>>>
>>> My gut reaction is to agree - the current rule, while it takes some
trivial learning, is easy to understand and communicate and is reflected
well in other parts of the language.  Also, additions to object literal
syntax might make this more...weird:
>>>
>>>    x => { [abc](def = function() { huh() }) { blahblahblah } };
>>>
>>> "But it's an object literal, obviously!"
>>
>>
>> Yes, there's always a trade-off, some futures are foreclosed by syntax
changes of this sort.
>>
>> Is it worth it? Hard to say, crystal ball service not answering the
phone ;-). Still, the motivation for that strawman I wrote in 2011 lives on.
>>
>> /be
>
>
>
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>
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