How to push date from calendar into startAt() function in angularJS - angularjs

Question

angular.module('...', ['...'])
.controller('main', main);
function main($scope, $firebaseArray) {
$scope.assign = function() {
$scope.assigned = $scope.deviceName;
};
$scope.today = function () {
// must put to set hours before isostring
$scope.dth = new Date();
$scope.test = moment($scope.dth).format('YYYY-MM-DD');
console.log($scope.test);
// this console.log is to check if the date format is correct
};
$scope.today();
$scope.inlineOptions = {
customClass: getDayClass,
minDate: new Date(),
showWeeks: true
};
$scope.open1 = function () {
$scope.popup1.opened = true;
};
$scope.formats = ['dd-MMMM-yyyy', 'yyyy/MM/dd', 'dd.MM.yyyy', 'shortDate'];
$scope.format = $scope.formats[0];
$scope.altInputFormats = ['M!/d!/yyyy'];
$scope.popup1 = {
opened: false
};
$scope.dateOptionsM = {
formatYear: 'MM',
startingDay: 1,
minDate: new Date(2018, 0, 1, 0, 0, 0, 0),
minMode: 'month'
};
$scope.dateOptionsY = {
formatYear: 'yyyy',
startingDay: 1,
// minDate: start from which date
minDate: new Date(2018, 0, 1, 0, 0, 0, 0),
minMode: 'year'
};
function getDayClass(data) {
var date = data.date,
mode = data.mode;
if (mode === 'day') {
var dayToCheck = new Date(date).setHours(0, 0, 0, 0);
for (var i = 0; i < $scope.events.length; i++) {
var currentDay = new Date($scope.events[i].date).setHours(0, 0, 0, 0);
if (dayToCheck === currentDay) {
return $scope.events[i].status;
}
}
}
return '';
}
$scope.$watch('[assigned, test]', function(values) {
//UI for calendar function
var newtest = values[1];
var value = values[0];
var newRef = firebase.database().ref('editedData').child(value);
var hourRef = newRef.child('H');
$scope.halfhourlyData = $firebaseArray(hourRef.orderByChild('timestamp').limitToLast(48).startAt(newtest));
console.log(newtest);
// this console log only displays once
$scope.halfhourlyData.$loaded();
So what I want to do is to push the date that is set on the calendar into the startAt() function. However, upon testing, I realized that both logs only have been displayed once. Meaning that the value is not changing. However, on the HTML page the value does change and it uses $scope.dth. Is there a way for me to make the values change according to the calendar display? I'm using angular-bootstrap UI. Thanks!