Good one with the prototype. but if the object will be created with the class, the prototype is created automatically.

I did it almost the same. Yours is nicer.

I'm sure current tests would pass without it but consider the case:
iterable = [undefined, undefined, 'a', 'b', 'c']

That method didn't exist in earlier JS versions.

just the zen of python ;)
but the point I was focusing is the build-in filter

Enveloping a function into a class for no particular reason sure makes a lot of sense ;)

none of you read the title!
where is that filter???
checkout my solution!

this solution does also use a foor-loop

beatiful

just for arguments sake, i wouldnt make human an interface since men and women share attributes, not just behaviors

Thank you very much for your reply ;)

It's a bitwise OR operator which in this case (against 0) essentially cuts of all non integers. Here it's used as a somewhat crude and hacky way to avoid Math.floor() or parseInt().

My advise would be to be careful using it in your projects. The | 0 is easily overlooked and can leave your future you searching forever where your math doesn't add up. Math.floor() does a better job at being self-explanatory. Since the example above is very short, the | 0 doesn't hurt for the simple purpose it serves.

Also look at stanleyvarga's comment. He also makes a solid point not to use it everywhere.

What means this "|" in Javascript ?

But it makes it easier to read.