javascript - $scope.scheduler is undefined in AngularJS -

i have been working angularjs v1.4.1 , daypilot v8.1.17 making this tutorial.

it working fine have problems when want load events external server returns events in json format.

view.html

<div ng-controller="viewschedulerdpctrl" >   <daypilot-scheduler id="scheduler" daypilot-config="schedulerconfig" daypilot-events="events" ></daypilot-scheduler> </div> 

schedulerdp.js

'use strict';      var app = angular.module('moduleapp')     app.controller('viewschedulerdpctrl', function($scope, $timeout, aircraftservice,flightservice) {         $scope.schedulerconfig = {           scale: "hour",           days: 5,           startdate: new date(),           timeheaders: [               { groupby: "month"},               { groupby: "day", format: "d" },               { groupby: "hour", format: "hh:mm" }           ]         };          $timeout(function() {           loadresources();           loadevents($scope.scheduler.visiblestart(), $scope.scheduler.visibleend()); // line doesn't work, scheduler got undefined         });          var loadresources=function() {            aircraftservice.getallaircrafts().then(function(aircrafts){             $scope.schedulerconfig.resources = aircrafts;            });         }          function loadevents(from, to) {           flightservice.getflights(from,to).then(function(flights){              $scope.schedulerconfig.startdate = from;               $scope.schedulerconfig.days = math.floor(new daypilot.timespan(to.gettime() - from.gettime()).totaldays());               $scope.events = flights;           });         }       }); 

the scheduler loads resources correctly doesn't display events, when see chrome console log displays error:

when put break point line gives error seems empty:

does know doing wrong?

i got problem when use in ionic app , put in found $scope.scheduler in $scope.$$childhead.$$childhead.scheduler