How to wait till the response comes from the http request in angularjs

Question

I am using some data which is from a RESTful service in multiple pages  So I am using angular factories for that  So  I required to get the data once from the server  and everytime I am getting the data with that defined service  Just like a global variables  Here is the sample   var myApp    angular module  myservices         myApp factory  myService   function  http         http  method  GET   url   my url    success function result           return result                In my controller I am using this service as   function myFunction  scope  myService         scope data   myService      console log  data name   scope data name       Its working fine for me as per my requirements  But the problem here is  when I reloaded in my webpage the service will gets called again and requests for server  If in between some other function executes which is dependent on the  defined service   It s giving the error like  something  is undefined  So I want to wait in my script till the service is loaded  How can I do that  Is there anyway do that in angularjs

User · Answer

for people new to this you can also use a callback for example:

In your service:

.factory('DataHandler',function ($http){

   var GetRandomArtists = function(data, callback){
     $http.post(URL, data).success(function (response) {
         callback(response);
      });
   } 
})

In your controller:

    DataHandler.GetRandomArtists(3, function(response){
      $scope.data.random_artists = response;
   });

User · Answer

You should use promises for async operations where you don t know when it will be completed  A promise  represents an operation that hasn t completed yet  but is expected in the future    https   developer mozilla org en docs Web JavaScript Reference Global Objects Promise   An example implementation would be like   myApp factory  myService   function  http         var getData   function                 Angular  http   and then   both return promises themselves          return  http  method  GET   url   my url    then function result                   What we return here is the data that will be accessible                 to us after the promise resolves             return result data                           return   getData  getData          function myFunction  scope  myService        var myDataPromise   myService getData        myDataPromise then function result                 this is only run after getData   resolves         scope data   result         console log  data name   scope data name               Edit  Regarding Sujoys comment that  What do I need to do so that myFuction   call won t return till  then   function finishes execution    function myFunction  scope  myService         var myDataPromise   myService getData         myDataPromise then function result               scope data   result            console log  data name   scope data name                 console log  This will get printed before data name inside then  And I don t want that           Well  let s suppose the call to getData   took 10 seconds to complete  If the function didn t return anything in that time  it would effectively become normal synchronous code and would hang the browser until it completed    With the promise returning instantly though  the browser is free to continue on with other code in the meantime  Once the promise resolves fails  the then   call is triggered  So it makes much more sense this way  even if it might make the flow of your code a bit more complex  complexity is a common problem of async parallel programming in general after all

User · Answer

I was having the same problem and none if these worked for me  Here is what did work though     app factory  myService   function  http        var data   function  value                return  http get value              return   data  data         and then the function that uses it is     vm search   function value             var recieved data   myService data value            recieved data then              function fulfillment                   vm tags   fulfillment data                 function                    console log  Server did not send tag data                          The service isn t that necessary but I think its a good practise for extensibility  Most of what you will need for one will for any other  especially when using APIs  Anyway I hope this was helpful

User · Answer

FYI  this is using Angularfire so it may vary a bit for a different service or other use but should solve the same isse  http has  I had this same issue only solution that fit for me the best was to combine all services factories into a single promise on the scope  On each route view that needed these services etc to be loaded I put any functions that require loaded data inside the controller function i e  myfunct   and the main app js on run after auth i put    myservice  loaded   then function     rootScope myservice   myservice       and in the view I just did  ng-if  myservice  ng-init  somevar myfunct      in the first parent view element wrapper so the controller can run everything inside  myfunct     without worrying about async promises order queue issues  I hope that helps someone with the same issues I had

[angularjs] How to wait till the response comes from the $http request, in angularjs?

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