Array extras and Objects

Rick Waldron waldron.rick at gmail.com
Thu Dec 1 05:33:31 PST 2011


On Dec 1, 2011, at 8:04 AM, David Bruant <bruant.d at gmail.com> wrote:

> Le 01/12/2011 08:47, Andrea Giammarchi a écrit :
>> Let's say this is an attempt to bring some new, easy to implement,
>> method for the native Object.prototype
>> Specially about forEach, the most used Array.prototype method out there,
> That's quite an ambitious statement. I use forEach, but I think I use
> push, concat, every/some, map and reduce quite often as well and I
> wouldn't be able to tell which I use more often (probably push).
> 
>> it's quite clear JS developers would like to have similar method to
>> iterate over objects, as key:value pairs rather than index:value.
> It seems that iterators [1] could do what you need. In this proposal (so
> very likely to be in ES.next), you can see this example:
> -----
> for ([key, val] of items(x)) {
>    alert("x." + key + " = " + val);
> }
> -----
> 
> There is even the possibility for you to define your own iterator on
> your objects.
> 
>> Almost every framework/library out there has an "error prone"
>> each(obj, callback) method, able to automagically recognize if the
>> passed obj is an array, an arrayLike, or an object.
>> A classic failing scenario is a function used as object, where the
>> length property won't mean it's an arrayLike entity.
> If some library authors think that an array is an object with a 'length'
> property,

The precedent was set by DOM APIs (eg NodeList)


> I think that they should learn JavaScript and that is not a
> reason to add a language feature.
> 
> David
> 
> [1] http://wiki.ecmascript.org/doku.php?id=harmony:iterators
> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss


More information about the es-discuss mailing list