Pure win: Array.from and Array.of

Brendan Eich brendan at mozilla.com
Sun Jul 10 13:35:38 PDT 2011


On Jul 10, 2011, at 12:02 PM, Dmitry A. Soshnikov wrote:

> On 10.07.2011 22:44, Brendan Eich wrote:
>> 
>> On Jul 10, 2011, at 10:40 AM, Dmitry A. Soshnikov wrote:
>> 
>>> On 10.07.2011 21:23, Brendan Eich wrote:
>>>> 
>>>> On Jul 10, 2011, at 10:18 AM, Rick Waldron wrote:
>>>> 
>>>>> The more I think about it, I still can't come up with any really exciting use cases where Array.of would outshine anything that already exists. I say strike it from the wishlist.
>>>> 
>>>> Higher-order programming with Array as constructing-function bites back for the single-number-argument case. That's where Array.of helps.
>>>> 
>>> 
>>> You mean when `Array` itself is passed as an argument?
>>> 
>>> var o = (function (ArrayConstructor, ...rest) {
>>>     return ArrayConstructor(...rest);
>>> })(Array, 10, 20, 30);
>> 
>> Yes. Now consider the case where you leave out the 20 and 30.
>> 
> 
> return ArrayConstructor(rest[0]) ?

The called function taking ArrayConstructor cannot assume it was passed only one trailing parameter captured by ...rest!


> May I ask to show nevertheless how you want to apply here Array.of?

You would pass Array.of instead of Array, of course.


> P.S.: 
> 
> If this is a wish-list of extending standard array lib, we can consider also the following:

A postscript is no place for more wish list items. See the subject: and start a new thread.

/be
> 

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