Node.js: Best way to perform multiple async operations, then do something else?

Question

In the following code I am trying to make multiple (around 10) HTTP requests and RSS parses in one go.

I am using the standard forEach construct on an a

Answer 1

using a copy of the list of url as a queue to keep track of arrivals makes it simple: (all changes commented)

var q=feedsToFetch.slice(); // dupe to censor upon url arrival (to track progress)

feedsToFetch.forEach(function (feedUri)
{   
        feed(feedUri, function(err, feedArticles) 
        {
            if (err)
            {
                throw err;
            }
            else
            {
                articles = articles.concat(feedArticles);
            }
            q.splice(q.indexOf(feedUri),1); //remove this url from list
            if(!q.length) done(); // if all urls have been removed, fire needy code
        });
 });

function done(){
  // Code I want to run once all feedUris have been visited

}

in the end, this is not that much "dirtier" than promises, and provides you chance to reload un-finished urls (a counter alone wont tell you which one(s) failed). for this simple parallel download task, it's actually going to add more code to your project implement Promises than a simple queue, and Promise.all() is not in the most intuitive place to stumble across. Once you get into sub-sub-queries, or want better error handling than a trainwreck, i strongly recommend using Promises, but you don't need a rocket launcher to kill a squirrel...