This comment thread reminds me a bit of "The Emperor's new clothes". I think the code for sieve (even though I understood what it did) is way too unnecessarily confusing and I would not want to see it in a project I'm on.

However, I do appreciate the usefulness of lazy evaluation. Still, I think this documentation could benefit by not making outlandish claims ("it will change the way you think") and just saying the author has implemented lazy evaluation in javascript (and maybe link to the wikipedia article on lazy evaluation and this stack overflow to explain why it's useful: http://stackoverflow.com/questions/2151226/what-are-the-adva...)