Paypal recently had an interesting follow-up talk "9 anti-patterns for node.js t...

barosl · on Nov 26, 2014

It is surprising to me that they recommend callbacks over promises! I had no idea that promises require higher CPU resources.

spion · on Nov 27, 2014

Hmm, those are strange results indeed. I would not be surprised if those measurements were made a year ago. Back then, promises were really slow.

But then bluebird came out and changed everything, and many of the other promise libraries followed suit. Most promise libs are now really lightweight (with the only remaining exception being Q).

See https://gist.github.com/spion/6990910 ; http://spion.github.io/posts/why-i-am-switching-to-promises.... ; https://github.com/spion/async-compare/blob/master/latest-re... -

For example, bluebird (and most other promise libraries today) have 2 to 3 times lower overhead than caolan's async and are comparable to the most hand-optimized raw callbacks.