An Angular Service for Queueing Alerts

Alerts.js

/** 
 * An angular service for managing alerts.
 * Alerts reference the action from which they were generated
 * via an actionID.  Alerts can be closed individualy, in
 * groups by action ID, or all of them can be cleared at once.
 * 
 * Designed primarily to work with Bootrstrap UI alerts but
 * could easily be used with other alert paradigms.
 */
app.factory("alertService", function () {
    // stores arrays of alerts indexed by action ID
    var alertGroups = {};
    return {
        // Get a reference to the alertGroups object
        getAlerts: function () {
            return alertGroups;
        },
        // generic method for adding an alert
        addAlert: function (type, actionID, message) {
            if (alertGroups[actionID] == undefined)
                alertGroups[actionID] = [];
            alertGroups[actionID].push({ type: type, message: message });
        },
        // adds an info alert
        addInfo : function (actionID, message) {
            this.addAlert('info',actionID,message);
        },
        // adds a success alert
        addSuccess: function (actionID, message) {
            this.addAlert('success', actionID, message);
        },
        // adds a warning alert
        addWarning: function (actionID, message) {
            this.addAlert('warning', actionID, message);
        },
        // adds an error alert
        addError: function (actionID,message) {
            this.addAlert('danger', actionID, message);
        },
        // closes an alert
        closeAlert : function (actionID,index) {
            alertGroups[actionID].splice(index, 1);
        },
        // clear all alerts for one action ID
        clearActionAlerts: function (actionID) {
            alertGroups[actionID] = [];
        },
        // clears absolutely all alerts
        clearAllAlerts : function () {
            alertGroups = {}
        },
        // generates an action ID
        getGuid : function(){
            return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {        
                var v = new Uint8Array(1);
                if (window.crypto == undefined) {
                    window.msCrypto.getRandomValues(v);
                }
                else {
                    window.crypto.getRandomValues(v);
                }
                v = v[0]/255;
                var r = v*16|0, v = c == 'x' ? r : (r&0x3|0x8);
                return v.toString(16);
            });
        }
    }
});

controller.js

app.controller('myController',['$scope','alertService',function($scope,alertService){
  // add a reference to the alerts in the alerts service to this scope
  $scope.alerts = alertService.getAlerts(),
  // close an alert using the alerts service
  $scope.closeAlert = alertService.closeAlert,
  $scope.doSomething = function(){
    var actionID = alertService.getGuid();
    alertService.addInfo(actionID,"We're doing something!");
  }
}]);

index.html

<!-- snippet /-->
<div id="alerts" ng-repeat="(actionID,alertGroup) in alerts">
    <uib-alert ng-repeat="alert in alertGroup"
               type="{{alert.type}}" close="closeAlert(actionID,$index)"
               dismiss-on-timeout="{{alert.type == 'info'?99999:5000;}}">
        {{alert.message}}
    </uib-alert>
</div>
<!-- snippet /-->