Hacker News new | comments | show | ask | jobs | submit login
What concurrency in Node.js could have been (ericjiang.com)
5 points by erjiang 1087 days ago | hide | past | web | 4 comments | favorite



Using asyncawait (https://github.com/yortus/asyncawait):

    var bakeCookies = async (function(cookie_mix) {
      print("Baking cookies...");
      var oven = new Oven(cookie_mix);
      var cookies = await (oven.bake(15));  // bake for fifteen minutes
      cookies.decorate();
      return cookies;
    });

It's plain JavaScript, concurrent, and works with plain node.js, unlike StratifiedJS.


So since it seems to me that this article entirely failed to mention why the callback pattern was harmful could someone else?


I've described some in the post I linked at the beginning, and many many others have described similar things. I've cribbed these from TJ Holowaychuk's recent post and added some others:

* callbacks are not logical for expressing sequential logic

* you end up with deeply nested code when having many sequential actions

* you may get duplicate callbacks

* you may not get a callback at all (lost in limbo)

* you may get out-of-band errors

* emitters may get multiple “error” events

* missing “error” events sends everything to hell

* often unsure what requires “error” handlers

* “error” handlers are very verbose

* callbacks suck

* too many different libraries to "fix" callbacks that each have their own problems

* e.g. easy to lose errors in Q promises

* varying performance of various promises/async libraries

* "best" async library constantly changes

* callback style is the only common api, so you end up with wrappers for each library x library combination

* sometimes forget whether a function uses a callback, returns a promise, is a generator, returns a stream, returns something that looks like a promise

* some libraries may not call callback asynchronously

and more. Callbacks have gotten a reputation as a dead horse that people like to beat on.


The point about fibers is incorrect. I posted a detailed comment on your blog.




Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | DMCA | Apply to YC | Contact

Search: