eventBus.js

app.factory("EventBus", function() {
    var eventMap = {};

    var EventBus = {
        on : function(eventType, handler) {
            //multiple event listener
            if (!eventMap[eventType]) {
                eventMap[eventType] = [];
            }
            eventMap[eventType].push(handler);
        },

        off : function(eventType, handler) {
            for (var i = 0; i < eventMap[eventType].length; i++) {
                if (eventMap[eventType][i] === handler) {
                    eventMap[eventType].splice(i, 1);
                    break;
                }
            }
        },

        fire : function(event) {
            var eventType = event.type;
            if (eventMap && eventMap[eventType]) {
                for (var i = 0; i < eventMap[eventType].length; i++) {
                    eventMap[eventType][i](event);
                }
            }
        }
    };
    return EventBus;
});