How to fetch child node inside nested firebase DB

Question

Hi,I was to fetch only the nodes where category = "Tribal" and return it as firebase array object.Thanks in advance.

Angular Service CODE:

this.getSpecialTourPackage = function(){
 var dbRef = firebase.database().ref('states').child('itineraries');
 return $firebaseArray(dbRef);
};

Angular Controller CODE:

if(_category != undefined && _category == 'Tribal'){
    var loadedResult = [];
    var resultArray = indiaTourService.getSpecialTourPackage();
    resultArray.$loaded().then(function(data){
    data.forEach(item =>{
    loadedResult.push(item);
    $scope.itineraries = _.where(loadedResult,{ category : "Tribal"});
    });
  });
}