Bluebird – A full-featured, fast promises library for JavaScript

https://github.com/petkaantonov/bluebird

by esailija • 13 years ago

90 42 13 years ago

spion6• 13 years ago

Some really impressive optimization techniques used in this library :)

What's also really impressive is that ultra-fast means callback-level performance. And that performance is achieved even though promises are exception-safe (and don't crash the process like exceptions in callbacks ;)

In fact, this library may become the turning point that causes node.js userland to start switching to promises...

onestone• 13 years ago

Impressive indeed. A post by the author in the main NodeJS group (https://groups.google.com/forum/#!forum/nodejs) would be great.

scotth• 13 years ago

Like what?

spion6• 13 years ago

Like function templating using the Function constructor, try-catch wrapping, closure avoidance and many more. The source is a goldmine of JS optimization techniques (some V8-specific, some not so much)

andreypopp2• 13 years ago

Kew[1] is still faster, working on a pull request with updated benchmarks which include Kew.

[1] https://github.com/Obvious/kew

andreypopp2• 13 years ago

Ok, sometimes kew is faster, sometimes bluebird, submitted a PR

spion6• 13 years ago

Here are some results from my benchmark [1]

results for 20000 parallel executions, 1 ms per I/O op

  file                   time(ms)  memory(MB)
  promiseishBluebird.js      1076       76.08
  async.js                   2634      113.79
  promiseishKew.js           2654      123.50
  promiseishQ.js            56508      804.21

note: async.js is basically waterfall from https://github.com/caolan/async

[1] https://github.com/spion/async-compare

davexunit• 13 years ago

This isn't related to the library, but promises in Javascript are much different than what I learned about promises in Scheme. In Javascript, promises seem to be about asynchronous operations. In Scheme (and other languages?), promises are used for lazy evaluation. Scheme provides the delay and force forms for this. Now I need to make sure that I don't get confused about this in the future.

zeckalpha• 13 years ago

Now I need to make sure that I don't get confused about this in the future.

Are you going to delay or force that?

ufo• 13 years ago

For a functional programming analogy, JS promises are more like monads than about lazy evaluations. I don't know if there is a good Scheme analogy because in Scheme you can use call/cc and friends while in JS you are forced to write your async code in explicit continuation passing style (promises are just a way to make this a bit more manageable).

j_m_b• 13 years ago

http://this-plt-life.tumblr.com/post/55420560033/when-somebo...

6cxs2hd6• 13 years ago

Another fan of that blog.

I imagine you could re-caption the "Simon Peyton-Jones adding the IO Monad to Haskell" GIF [1] to serve this topic, too.

[1] http://this-plt-life.tumblr.com/post/44462204757/simon-peyto...

deeteecee• 13 years ago

hahaha, nice

antihero3• 13 years ago

I'm not sure if I'm doing things quite right, but I got a simply Postgres server script working.

https://gist.github.com/radiosilence/6826930

Could this be improved?

esailija5• 13 years ago

It looks like you are creating wrappers manually, that could be improved. Look into both overloads of [`Promise.promisify`](https://github.com/petkaantonov/bluebird/blob/master/API.md#...)

antihero3• 13 years ago

I did try to Promisify the pg library but it didn't seem to work, and just broke :(

statico• 13 years ago

If it's useful, here's an app I converted to promises: https://github.com/artillery/pull-request-viewer/blob/master...

It uses Q, not bluebird, but should still be relevant.

acemarke• 13 years ago

I'm finally starting to wrap my head around the concepts involved in promises, and was able to find a couple places to use them in my current rewrite of a JS codebase. However, my initial search doesn't show any articles describing why I should pick one of these over the other, particularly if they all implement the Promises/A+ spec.

Would someone be kind enough to give me some idea what the meaningful differences are between Q, when, and bluebird?

dclowd9901• 13 years ago

What you want is a library that is fast (like the one mentioned), and is easy to debug. Most promises libraries don't implement a good stack trace. The one submitted for this article has what looks like a pretty amazing stack tracer, and is quite fast. If it truly follows the Promises A+ spec (which I'm sure it does), it's probably your best bet.

domenicd2• 13 years ago

I will speak mostly to Q, since I am a co-maintainer.

Q has historically stemmed from the work of Mark Miller, one of the authors of the E programming language, from which JavaScript promises are largely inspired. As such, it aligns with his larger goals for a promise ecosystem, which include object-capability security and using promises as proxies for remote objects. For an example of promises applied in these contexts, see his paper at [1].

In practice, all of this is somewhat theoretical, as Q also serves a large constituency of "normal" promise users in Node and the browser. There, it differentiates itself via a focus on features and integrity over speed (mainly as a matter of prioritization; we like speed too!); excellent Node.js integration [2]; and an internal system which allows promises for remote objects via Q-Connection [3] (but also gives some nice methods for promises for objects etc. for the same-machine case [4]).

I would say that Q is my favorite library to work with, as it has thought out its design choices in a depth I don't see in the other libraries---or perhaps more accurately, the choices they have made don't align with my sense of craftsmanship as well :). That said, you should probably not use it if your concern is speed. We have always taken the position that, while speed is nice, most of the time you are doing an asynchronous operation anyway, so any overhead from the promise library will matter very little.

[1] http://research.google.com/pubs/pub40673.html [2]: https://github.com/kriskowal/q/wiki/API-Reference#interfacin... [3]: https://github.com/kriskowal/q-connection [4]: https://github.com/kriskowal/q/wiki/API-Reference#promise-fo...

rektide• 13 years ago

"ref_send", the ability to create a deliverable value, would be my core linkage on Q and more-so promises (as not an author) http://waterken.sourceforge.net/ .

The background is interesting, but I'm not sure what value an association with historical context brings. I've tried other promise libraries, but stub my toe on missing capabilities I'm used to, or end up distracted with mechanics. I don't think I've ever found myself saying, gee, would that this be closer to ref_send, but then again almost all implementations happen to tack close to. So, uh, Domenic does have a more useful account of Q. Mostly here to drop some ref_send. ;)

domenicd2• 13 years ago

As a co-maintainer of Q, and author of the ES6 promise spec, this is extremely impressive work. I have had the privilege of watching it develop over the last few weeks, and am nothing short of amazed with what the author has done. The speed of this library opens up many doors for putting promises in places where previously some might have considered them not-low-level enough.

dmak2• 13 years ago

I'm curious, could you explain why this is impressive and why it may or may not be better than Q?

shuzchen• 13 years ago

Looks awesome, I've been using JS Promises recently and it's made control flow a lot easier to handle. I've been using Vow, because I like having an .always() that gets called after the promise was handled (rejected or fulfilled), but sadly that library eats tracebacks (at least, I can't figure out a way to do it). Bluebird looks promising, but IE<9 isn't supported at the moment (https://github.com/petkaantonov/bluebird/issues/3). Rules it out for most of my projects.

oakaz2• 13 years ago

I code and enjoy JavaScript for years, and rarely feel like my heart feels feels squeezed when I look at a JavaScript library.

Call me hater, but, I would never use it and anything depending on it.

bronson• 13 years ago

You're a hater if you don't at least attempt to explain your feeling. Why even post that? Did you think you were participating in a poll?

oakaz2• 13 years ago

Yes, I can explain: the source code is horrible, readme is horrible.

What it does: not clear.

How it's different: not clear.

Project name: bird?!

Modularity: Poor. one single JavaScript file with hundreds of lines :(

Duplicate effort, nothing new but more confuse.

I'm just tired of seeing shitty Promises libraries. And I'm a huge hater for those.

Here is a good one that I liked: https://github.com/puffnfresh/fantasy-promises

cwmma2• 13 years ago

I'm not really seeing the speed on a fairly realistic perf [1] involving communicating with a web worker. Wrote a big blog post looking into this a couple weeks back [2].

[1] http://jsperf.com/promise-comparisons/55 [2]: http://calvinmetcalf.com/post/61761231881/javascript-schedul...

esailija5• 13 years ago

When I say performance, I mean throughput not latency. That's why there are no latency benchmarks.

Also, in your benchmark you do output in bluebird section with console.log. Maybe try http://jsperf.com/promise-comparisons/50.

cwmma2• 13 years ago

that one uses window.addEventListner which gives an advantage to libraries that prefer that to ones that use that one first over ones that use messageChannel first. here is a fixes one[1], looks like everything using mutation observer is about the same throughput.

My background is that I've been trying to create a promise library that just creates without also being underscore for promises [1]

What sort of performance are we talking about that we are able to test without really measuring other things. For instance when was able to dominate many of the perfs by actually doing many of them synchronously in cases where other libraries would force it async.

[1] http://jsperf.com/promise-comparisons/59 [2]: https://github.com/calvinmetcalf/lie

Bluebird – A full-featured, fast promises library for JavaScript

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