javascript - Define a promise creating a new Service Object -

i have question promise system in angularjs , creation of services. have service called customer:

angular.module("app").factory("customer", ["customerdbservices", "officeslist", "$q",     function(customerdbservices, officeslist, $q){         return function(customerid){              var self = this;              //attributes             this.name = null;             this.id = null;             this.code = null;             this.isvisible = 1;             this.showoffices = true;             this.offices = new officeslist();              //constructor             if(typeof customerid !== "undefined"){                 var metacustomer = customerdbservices.find({id:customerid}, function(){                     self.name = metacustomer.results.customer_name;                     self.id = metacustomer.results.customer_id;                     self.code = metacustomer.results.customer_internal_code;                     self.isvisible = metacustomer.results.customer_is_visible;                     self.getoffices();                 });             }              //add office customer             this.addnewoffice = function(){                 self.offices.addnewoffice();             };              //remove office customer             this.removeoffice = function(officeindex){                 self.offices.removeoffice(officeindex);             };              //show offices             this.toggleofficevisibility = function(officeindex){                 self.offices.toggleofficevisibility(officeindex);             }; }]);  

in "constructor" part of service there ajax call service loads attributes of customer database. async task. how can create promise in situation? use customer service this:

var customer = new customer(id); 

and like

var customer = new customer(id).then(         function(){...}, //success         function(){...} //error ); 

to need promise. have program method create() within customer service?

angular.module("app").factory("customer", ["customerdbservices", "officeslist", "$q",     function(customerdbservices, officeslist, $q){         return function(customerid){              var self = this;              //attributes             this.name = null;             this.id = null;             this.code = null;             this.isvisible = 1;             this.showoffices = true;             this.offices = new officeslist();              //costructor             this.create = function(){                 if(typeof customerid !== "undefined"){                     var rest = $q.defer();                     var metacustomer = customerdbservices.find({id:customerid}, function(){                         self.name = metacustomer.results.customer_name;                         self.id = metacustomer.results.customer_id;                         self.code = metacustomer.results.customer_internal_code;                         self.isvisible = metacustomer.results.customer_is_visible;                         self.getoffices();                          rest.resolve("ok!");                     });                     return rest.promise;                 }             }              ...             ...             ... }]); 

and use stuff this?

var customer = new customer(); customer.create(id).then(     function(){...},     function(){...}, ) 

isn't there way call "new customer" , receive promise? thank in advance!

like said in comment recommend against approach. putting complex asynchronous logic in constructor confusing , not make or clear api.

that said, don't need .create method.

the trick is: if function called constructor returns object in javascript - returned instead of this value.

sparing whole angular around it:

function(customerdbservices, officeslist, $q){     return function(customerid){          var p = $q.defer();         var = p.promise; // our 'that' promise          //attributes         that.name = null;         that.id = null;         that.code = null;         that.isvisible = 1;         that.showoffices = true;         that.offices = new officeslist();         // use `that` instead of in additional code          if(typeof customerid !== "undefined"){             var metacustomer = customerdbservices.find({id:customerid}, function(){                 self.name = metacustomer.results.customer_name;                 self.id = metacustomer.results.customer_id;                 self.code = metacustomer.results.customer_internal_code;                 self.isvisible = metacustomer.results.customer_is_visible;                 self.getoffices();                 that.resolve("ok!");            });        }         return that; // return promise here.     }