JavaScript Pub-Sub

pub-sub.js

var pubsub = (function () {
  'use strict';
  var observers = [];
  return {
    subscribe: function (events, listener) {
      var event, i;
      events = events.split(' ');
      for (i in events) {
        if (events.hasOwnProperty(i)) {
          event = events[i];
          (observers[event] || (observers[event] = [])).push(listener);
        }
      }
    },
    unsubscribe: function (event, listener) {
      var value, key;
      for (
        value = observers[event] || [];
        listener && (key = value.indexOf(listener)) > -1;
      ) {
        value.splice(key, 1);
      }
      observers[event] = listener ? value : [];
    },
    publish: function (event) {
      var args = Array.prototype.slice.call(arguments, 1);
      for (
        var value = observers[event], key = 0;
        value && key < value.length;
      ) {
        value[key++].apply(this, args);
      }
    }
  };
}());