array comprehensions

[backspaces]

I realize array comprehensions were removed from es6, apparently due to es7 being performance oriented, including parallelism.

BUT Coffeescript has made me addicted to the critters! Would it be out of scope to show an example, in es6, of building your own array comprehension, then ditto for es5? They may be the same, sigh.

[addyosmani]

I think we could show them as long as we include a note about them being dropped from ES6.

[backspaces]

That'd be great, thanks! And why folks might want help is performance:

Here's a jsperf on array comprenensions, for-loops, and alternatives.
​ ​http://jsperf.com/arraymap/12