angularProject/app/directives/selectedMeals.js

app.directive('selectedMeals',['$interval',function($interval){
  return {
    replace: true,
    resctrict: 'E',
    templateUrl: 'app/views/selected-meals.html',
    scope: {
      meals: '=',
    },
    controller: function($scope){
      $interval(function(){
        if(firebase.auth().currentUser){
          $scope.ref = firebase.database().ref().child('users').child(firebase.auth().currentUser.uid).child('meals');
        }
      },1000)
      $scope.unselect = function(i){
        if(firebase.auth().currentUser){
          var keys = Object.keys($scope.meals);
          $scope.meals[keys[i]].isSelected = false;
          $scope.ref.child(keys[i]).set($scope.meals[keys[i]]);
        }
      }
    }
  }
}])