javascript - AngularJS $http.get async execution order -

i did lot of coding in angularjs. after time started feel comfortable , got productive. unfortunately there 1 thing don't understand:

within project need data through $http.get , restful api server. started stumble first. after implementing promise ($q.defer etc , .then) @ functions processing data that's necessary continue, thought conquered problem.

but in code:

$scope.getobservationsbylocations = function() {         var promise = $q.defer();         var locationcount = 0;          angular.foreach($scope.analysisdata, function(loc) {   // each location             $http.get($scope.api + 'device?_format=json', {     // devices                 params: {                     location: loc.location.id                 }             }).then(function (resultdevices) {                 var data = angular.fromjson(resultdevices);                 promise.resolve(data);                 // each device in location                 angular.foreach(angular.fromjson(resultdevices).data.entry.map(function (dev) {                     http.get($scope.api + 'observation?_format=json', {     // observations                         params: {                             device: dev.resource.id                         }                     }).then(function (resultobservations) {                         var observations = angular.fromjson(resultobservations);                         // each obervation of device in location                         angular.foreach(observations.data.entry.map(function(obs) {                             $scope.analysisdata[locationcount].observations.push({observation: obs.resource});                         }));                      })                 }))             });             locationcount++         });         return promise.promise }; 

i can't understand in order commands executed. since use webstorm ide , it's debugging feature, more accurate don't know why commands executed in order don't understand.

thinking simple, included in foreach have executed before return reached, because $http.get's connected through .then's. following debugging information, function iterates on locationcount++ , returns promise before goes deeper (meaning after first .then() ).

what's about? did misunderstood part of angularjs concept?

or bad practice , should reach out different solution?

if context important/interesting: objects based on i.e. https://www.hl7.org/fhir/2015may/location.html#5.15.3

with javascript can create single thread applications, although e.g. here not guaranteed that.

but talking real world , real browsers, code sample running single thread (by way same thread used rendering css , html, @ least in firefox).

when comes asynchronous call

$http.get($scope.api + 'device?_format=json', {  

it says "hey, can later". , waits because must go on current thread.

then, once current task done return can start getting remote data.

proof? check fiddle:

console.log(1);  (var i=0;i<1000000;i++) settimeout(function(){     console.log(2); },0);  console.log(3); 

you see spike for loop? moment when registers settimeout asynchronous calls. still 3 printed before 2 because task not done until 3 printed.