Question

What’s the best way/library for handling multiple asynchronous callbacks? Right now, I have something like this:

_.each(stuff, function(thing){
   async(thing, callback);
});

I need to execute some code after the callback has been fired for each element in stuff.

What’s the cleanest way to do this? I’m open to using libraries.

Answer 1

There is a great library called Async.js that helps solve problems like this with many async & flow control helpers. It provides several forEach functions that can help you run callbacks for every item in a an array/object.

Check out:
https://github.com/caolan/async#forEach

// will print 1,2,3,4,5,6,7,all done

var arr = [1,2,3,4,5,6,7];

function doSomething(item, done) {
  setTimeout(function() {
    console.log(item);
    done(); // call this when you're done with whatever you're doing
  }, 50);
}

async.forEach(arr, doSomething, function(err) {
    console.log("all done");
});