Function.prototype.partial

[Andrea Giammarchi]

for code sake, the dynamic should copy and push, not just push

```js
Object.defineProperty(
  Function.prototype,
  'partial',
  {
    writable: true,
    configurable: true,
    value: function partial() {
      for (var f = this, a = [], i = 0; i < arguments.length; a[i] =
arguments[i++]);
      return function () {
        var args = a.slice(0);
        args.push.apply(a, arguments);
        return f.apply(this, a);
      };
    }
  }
);
```

Regards


On Sun, Oct 4, 2015 at 10:04 PM, Andrea Giammarchi <
andrea.giammarchi at gmail.com> wrote:

> I think his point was that in the functional programming way he is
> thinking about, you don't care about `this` at all so you can shim
> `partial` like:
>
> ```js
> Object.defineProperty(
>   Function.prototype,
>   'partial',
>   {
>     writable: true,
>     configurable: true,
>     value: function partial() {
>       for (var a = [null], i = 0; i < arguments.length; a[++i] =
> arguments[i - 1]);
>       return this.bind.apply(this, a);
>     }
>   }
> );
> ```
>
> The dynamic `this` alternative seems quite straight forward anyway
>
> ```js
> Object.defineProperty(
>   Function.prototype,
>   'partial',
>   {
>     writable: true,
>     configurable: true,
>     value: function partial() {
>       for (var f = this, a = [], i = 0; i < arguments.length; a[i] =
> arguments[i++]);
>       return function () { a.push.apply(a, arguments); return
> f.apply(this, a); };
>     }
>   }
> );
> ```
>
> Regards
>
>
>
>
> On Sun, Oct 4, 2015 at 8:04 PM, Jordan Harband <ljharb at gmail.com> wrote:
>
>> (note, it couldn't be a direct proxy to `bind` because `bind(null)`
>> permanently sets the "this" value (ie, `(function () { return this
>> }).bind(null).call([])` will return null or the global object, not the
>> empty array. the polyfill would be a bit trickier, and couldn't use "bind"
>> under the hood without changes to bind itself)
>>
>> On Sun, Oct 4, 2015 at 8:06 AM, Tim Ruffles <oi at truffles.me.uk> wrote:
>>
>>> It'd be nice to add Function.prototype.partial, which is exactly like
>>> `.bind` without the `this`-setting first argument.
>>>
>>> Adding it would have benefits:
>>>
>>> - `.bind(null, ...` is newbie confusing and ugly in functional code[1]
>>> - `.bind(null, ...` is a very common idiom[2]
>>> - `.partial` is intention revealing: it's clear you're writing
>>> functional code that doesn't care about `this`
>>>
>>> Adding it seems low cost, and is backwards compatible:
>>>
>>> - implementors could literally make it a proxy to `.bind` if they want
>>> to get it done fast
>>> - shimmable
>>> - not new functionality, just a subset of existing functionality
>>>
>>> Cheers,
>>>
>>> Tim
>>>
>>> @timruffles
>>>
>>> - [1] I've been teaching newbies Javascript/Node.js for years, and if
>>> you take a 'functions first' approach it's complexity you have to tell them
>>> to ignore
>>> - [2] see github -
>>> https://github.com/search?l=javascript&q=%22.bind%28null%22&ref=searchresults&type=Code&utf8=%E2%9C%93
>>>
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>>
>>>
>>
>> _______________________________________________
>> es-discuss mailing list
>> es-discuss at mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>>
>
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