learnyounode-9-module.js

// "But for this exercise, try and do it without any external helper library."
// this version is my (sent1nel's) work
var http = require('http')
  , events = require('events')
  , util = require('util')
  , bl = require('bl')

function Server() {};

util.inherits(Server, events.EventEmitter);

Server.prototype.get = function (id) {
  var self = this;
  http.get(process.argv[id + 2], function (res) {
    res.pipe(bl(function(err, data) {
      if (err) return console.error(data);
      self.emit('data', id, data.toString());
    }));
  });
}

module.exports = new Server;

learnyounode-9.js

var server = require('./9-module')

var buffers = []
  , received = 0

server.on('data', function(id, buffer) {
  received++;
  buffers[id] = buffer;

  if (received == 3) this.emit('done');
});

server.on('done', function() {
  for (var i = 0; i < buffers.length; i++)
    console.log(buffers[i]);
});

for (var i = 0; i < 3; i++)
  server.get(i);