Except that if you're, say, performing nested iteration, you end up creating a whole crapload of closures, ballooning up memory usage and punishing the GC. A q

Except that if you're, say, performing nested iteration, you end up creating a whole crapload of closures, ballooning up memory usage and punishing the GC. A quick test show that coffeescript's iterator is about three times faster. http://pastie.org/3783184 http://pastie.org/3783184 Underscore's nice, but I really like Coffeescript's iterator sugar.