angularProject/app/controllers/SelectMenuPageController.js

app.controller('SelectMenuPageController',['$scope','$firebaseObject','$timeout','$interval',function($scope,$firebaseObject,$timeout,$interval){
  if(firebase.auth().currentUser){
    $scope.ref = firebase.database().ref().child('users').child(firebase.auth().currentUser.uid).child('meals');
  } else{
    $scope.ref = firebase.database().ref().child('meals');
  }
  $interval(function(){
    if(firebase.auth().currentUser){
      $scope.ref = firebase.database().ref().child('users').child(firebase.auth().currentUser.uid).child('meals');
    } else{
      $scope.ref = firebase.database().ref().child('meals');
    }

    $scope.ref.on('value', snap => {
      $timeout(function(){
        $scope.meals = snap.val();
      })
    })
  },1000)
  // var ref = firebase.database().ref().child('meals');

  $scope.mealType = 'breakfast';
  $scope.meals = [];
  $scope.selectedNumber = 0;

  $scope.selectMeal = function(i){
    if(firebase.auth().currentUser){
      var keys = Object.keys($scope.meals);
      //animating btn
      if(!$scope.meals[keys[i]].isSelected){
        var selectedMealsBtn = angular.element(document.querySelector('.selected-meals-btn'));
        selectedMealsBtn.addClass('selected-meals-btn-animate');
        $timeout(function(){
          selectedMealsBtn.removeClass('selected-meals-btn-animate');
        },500)
      }
      //animating btn
      $scope.meals[keys[i]].isSelected = true;
      $scope.ref.child(keys[i]).set($scope.meals[keys[i]]);
    } else{
      var loginPopupJQ = angular.element(document.querySelector('.login-popup'));
      loginPopupJQ.css('display','flex');
      $timeout(function(){
        loginPopupJQ.css('opacity','1');
      },50)
    }
  }

  $scope.ref.on('value', snap => {
    $timeout(function(){
      $scope.meals = snap.val();
    })
  })

}])