Basic Javascript PubSub Pattern

pubsub.js

//events - a super-basic Javascript (publish subscribe) pattern

var events = {
  events: {},
  on: function (eventName, fn) {
    this.events[eventName] = this.events[eventName] || [];
    this.events[eventName].push(fn);
  },
  off: function(eventName, fn) {
    if (this.events[eventName]) {
      for (var i = 0; i < this.events[eventName].length; i++) {
        if (this.events[eventName][i] === fn) {
          this.events[eventName].splice(i, 1);
          break;
        }
      };
    }
  },
  emit: function (eventName, data) {
    if (this.events[eventName]) {
      this.events[eventName].forEach(function(fn) {
        fn(data);
      });
    }
  }
};

Skhmt try events: Object.create( null )

var events = (function() {

    var events = {};

    function on(eventName, fn) {
        events[eventName] = events[eventName] || [];
        events[eventName].push(fn);
    }

    function off(eventName, fn) {
        if (events[eventName]) {
            for (var i = 0; i < events[eventName].length; i++) {
                if( events[eventName][i] === fn ) {
                    events[eventName].splice(i, 1);
                    break;
                }
            }
        }
    }

    function emit(eventName, data) {
        if (events[eventName]) {
            events[eventName].forEach(function(fn) {
                fn(data);
            });
        }
    }

    return {
        on: on,
        off: off,
        emit: emit
    };

})();

That’s iife