On: Transducers for JavaScript

[icholy]

I think it only iterates over the collection once.

[rymohr → icholy]

That and they're collection agnostic. I highly recommend watching Rich Hickey's talk for more background: https://www.youtube.com/watch?v=6mTbuzafcII

[msoad → icholy]

Then what happens to operations that access the collection? like third argument in JavaScript's native forEach?

[acjohnson55 → msoad]

That's what a zipper [1] is good for. It gives you access to the rest of a collection relative to the current position.

[1] http://en.wikipedia.org/wiki/Zipper_%28data_structure%29

[aeflash → msoad]

It's not supported. But if you're doing things right, you shouldn't need it.