Cool!
So for me, the point would be symmetry with Map and Set.
As such my poly would go like so:
```js
Object.defineProperty(Array.prototype, "append", {
writable: true,
configurable: true,
value: function(arg) {
this.push(arg);
return this;
}
});
```
(Which is basically what I end up doing with && in a => in reduce() calls...)
> On Wed, May 23, 2018 at 5:56 PM, Alexander Lichter <e...@lichter.io> wrote:
> > An optimization would be great because in comparison to the existing concat
> > method, rest/spread is significantly slower at the moment (see
> > https://jsperf.com/single-array-composition)
>
> There's a limit to how much optimization can address the fact that
> `[...original, ...additions]` has to create a new array. And creating the
> array is significant, as we can see in the difference between `concat` and
> `push`: https://jsperf.com/concat-vs-push-number-42
>
> I've often wanted an `Array.prototype.append` (often enough I've been known
> to add it on occasion; obviously only in app/page code, not in lib code). It
> would be a good addition in my view. I tend to suspect the name isn't
> web-safe, though. So that would need investigation and design.
>
> The polyfill is trivial:
>
> ```js
> Object.defineProperty(Array.prototype, "append", {
> value: function(...sources) {
> for (let o = 0, olen = sources.length; o < olen; ++o) {
> const source = sources[o];
> for (let i = 0, ilen = source.length; i < ilen; ++i) {
> this.push(source[i]);
> }
> }
> return this;
> },
> writable: true,
> configurable: true
> });
>
> ```
>
>
> I've avoided iterators and such as a first pass at optimization (and it seems
> to do okay: https://jsperf.com/push-vs-append-number-42/1). Didn't use
> `push.apply` because of the limits it has on it in some implementations. This
> version assumes all entries are array-like and should have their entries
> added to the array on which it's called. There are a lot of other designs one
> could make, though. Just one argument (you can always chain); a flattening
> version; etc., etc.
>
>
> -- T.J. Crowder
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