event pub&sub in Node.js

event_pub_sub_01.js

/**
 * Event_pub_sub with many to one
 *
 */
var after = function (times, callback) {
  var count = 0,
      results = {};

  return function (key, value) {
    results[key] = value;
    count ++;

    if (count === times) {
      callback(results);
    }
  };
}

// Usage
var done = after(2, render);
fs.readFile('', function (err,data) {
  done('template', data);
});

db.query('', function (err, db) {
  done('db', db);
});