The best pattern for handling async looping in Node.js

Question

I\'m new to Node and trying to ensure that I\'m using sane designs for a JSON-driven web app.

I\'ve got a bunch of data stored in Redis and am retrieving it through

Answer 1

but I can't help thinking that the i == replies.length-1 is a little untidy?

I've heard a lot of people say that. This is how I would do it by hand:

app.get("/facility", function(req, res, next) {
  rc.keys("FACILITY*", function(err, replies) {
    if (err) return next(err);
    var pending = replies.length;
    res.write("[");
    replies.forEach(function (reply) {
      rc.get(reply, function(err, reply) {
        res.write(reply);
        if (!--pending) {
          res.write("]");
          return res.end();
        }
        res.write(",");
      });
    });
  });
});

Obviously doing it by hand isn't too pretty, which is why people have it abstracted into a library or some other function. But like it or not, that is how you do an async parallel loop. :)

You can use the async library mentioned before to hide the nasty innards.