angularjs - How to handle multiple async tasks in angular.js and NgMap -

working on application geolocation using ngmap , angularjs. goal trail, markeur can browse set of points can exist given time. asynchronous spots browse ie have multiple asynchronous tasks work independently of others. me please resolve problem ?

the $scope.zoomer2 function role retrieve route 2 points (origin , destination) , trace in view.

 $scope.zoomer2 = function(event){       if (debut == null){          debut = event.latlng;          console.log(' debut == null '+debut);      } else if (fin == null){          fin = event.latlng;          $scope.directi.push(                  {origin:debut, destination:fin}          );          console.log(' fin == null '+fin);          console.log(' contenu de directi ');          console.log($scope.directi);           debut = null;          fin = null;               $timeout(function(){                 $scope.tracer(event);              }, 1000);       } else if (fin != null){          fin = null;          console.log(' fin != null => '+fin);      } else if (debut != null){          debut = null;          console.log(' debut != null => '+debut);      } } 

the $scope.getdistance function role calculate distance between 2 points

$scope.rad = function(x) {   return x * math.pi / 180; }; $scope.getdistance = function(p1, p2) {     var r = 6378137;     var dlat = $scope.rad(p2.lat() - p1.lat());     var dlong = $scope.rad(p2.lng() - p1.lng());     var = math.sin(dlat / 2) * math.sin(dlat / 2) +         math.cos($scope.rad(p1.lat())) * math.cos($scope.rad(p2.lat())) *         math.sin(dlong / 2) * math.sin(dlong / 2);     var c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a));     var d = r * c;     return math.ceil(d/10)*10; }; 

the $scope.tracer function role browse pointsarray index, problem asynchronous task cons both asynchronous tasking not work @ same time.

normally value $scope.pointsarray [z] must same outside , in $interval when z = 0.

but not case , don't know.

$scope.tracer = function(event){

    $scope.debut = null;     $scope.fin = null;     var map = $scope.map;     var zoom = map.getzoom();      z = $scope.directi.length-1;      $scope.pointsarray[z] = [];           ( var = 0; < map.directionsrenderers[z].directions.routes[0].legs[0].steps.length; i++){             console.log(' boucle  1', map.directionsrenderers[z].directions.routes[0].legs[0].steps[i]);             console.log(' la taille de  length '+map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path.length);              ( var j = 0; j < map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path.length; j++){                 console.log(' boucle 2 latitude longitude ', map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path[j].lat(), map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path[j].lng());                 $scope.pointsarray[z].push({'lat':map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path[j].lat(), 'lng':map.directionsrenderers[z].directions.routes[0].legs[0].steps[i].path[j].lng()});             }         }          $q.when().then(function(tabs = $scope.pointsarray[z]){              var deferred = $q.defer();             var j = 0;             console.log($scope.pointsarray[z]);              $interval(function(tabs = $scope.pointsarray[z]){                 console.log($scope.pointsarray[z]);                  if ( j >= $scope.pointsarray[z].length-1)                     return;                      console.log($scope.pointsarray[z][j].lat,$scope.pointsarray[z][j].lng);                     p1 = new google.maps.latlng($scope.pointsarray[z][j].lat,$scope.pointsarray[z][j].lng);                     p2 = new google.maps.latlng($scope.pointsarray[z][j+1].lat,$scope.pointsarray[z][j+1].lng);                      console.log(' *************************  1 ');                     console.log(' cc  1 ');                     distance = 0;                      $interval(function(){                         if (distance >= $scope.getdistance(p1, p2))                             return;                              distance = distance + 10;                             map.markers[z].setposition(p1);                             console.log(' la valeur de la distance est ===>>> '+distance);                             deferred.resolve(distance);                      }, distance);                     console.log(' *************************  2 ');                     console.log(' la valeur de j '+j);                     j++;              }, 1000);              return deferred.promise;         });}; 

help me please ?