johnloy
4/8/2016 - 9:26 PM

Simple PubSub implementation with JavaScript - taken from Addy Osmani's design patterns book -

var pubsub = {};
(function (q) {
  var topics = {},
    subUid = -1;
  q.subscribe = function (topic, func) {
    if (!topics[topic]) {
      topics[topic] = [];
    }
    var token = (++subUid).toString();
    topics[topic].push({
      token: token,
      func: func,
    });
    return token;
  };

  q.publish = function (topic, args) {
    if (!topics[topic]) {
      return false;
    }
    setTimeout(function () {
      var subscribers = topics[topic],
        len = subscribers ? subscribers.length : 0;

      while (len--) {
        subscribers[len].func(topic, args);
      }
    }, 0);
    return true;
  };

  q.unsubscribe = function (token) {
    for (var m in topics) {
      if (topics[m]) {
        for (var i = 0, j = topics[m].length; i < j; i++) {
          if (topics[m][i].token === token) {
            topics[m].splice(i, 1);
            return token;
          }
        }
      }
    }
    return false;
  };
})(pubsub);