How to return a resolved promise from an AngularJS Service using q

Question

My service is   myApp service  userService         http     q     rootScope     location   function  http   q   rootScope   location        var deferred      deferred    q defer        this initialized   deferred promise      this user           access  false            this isAuthenticated   function           this user             first name   First           last name   Last           email   email address com           access   institution                 return deferred resolve                     I m calling this in my config file via   myApp run       rootScope    userService   function  rootScope  userService        return userService isAuthenticated   then function response          if  response data user            return  rootScope  broadcast  login   response data           else           return userService logout                              However  it complains that then is not a function  Aren t I returning the resolved promise

User · Answer

Return your promise   return deferred promise  It is the promise API that has the  then  method   https   docs angularjs org api ng service  q  Calling resolve does not return a promise it only signals the promise that the promise is resolved so it can execute the  then  logic   Basic pattern as follows  rinse and repeat http   plnkr co edit fJmmEP5xOrEMfLvLWy1h p preview   lt  DOCTYPE html gt   lt html gt    lt head gt     lt script data-require  angular js    data-semver  1 3 0-beta 5           src  https   code angularjs org 1 3 0-beta 5 angular js  gt  lt  script gt     lt link rel  stylesheet  href  style css    gt     lt script src  script js  gt  lt  script gt   lt  head gt    lt body gt    lt div ng-controller  test  gt     lt button ng-click  test    gt test lt  button gt   lt  div gt   lt script gt    var app   angular module  app          app controller  test  function  scope  q         scope  test   function          var deferred    q defer          deferred resolve  Hi          return deferred promise               scope test function           scope  test          then function data           console log data                                  angular bootstrap document   app       lt  script gt

User · Answer

Try this   myApp service  userService           http     q     rootScope     location   function  http   q   rootScope   location          var deferred   q defer          this user             access  false                try               this isAuthenticated   function             this user               first name   First             last name   Last             email   email address com             access   institution                     deferred resolve                       catch               deferred reject               return deferred promise

User · Answer

Here s the correct code for your service   myApp service  userService         http     q     rootScope     location   function  http   q   rootScope   location         var user           access  false             var me   this       this initialized   false      this isAuthenticated   function            var deferred    q defer          user             first name   First           last name   Last           email   email address com           access   institution                 deferred resolve user         me initialized   true         return deferred promise                   Then you controller should align accordingly   myApp run       rootScope    userService   function  rootScope  userService        return userService isAuthenticated   then function user          if  user               You have access to the object you passed in the service  not to the response             You should either put response data on the user or use a different property          return  rootScope  broadcast  login   user email             else           return userService logout                              Few points to note about the service    Expose in a service only what needs to be exposed  User should be kept internally and be accessed by getters only  When in functions  use  me  which is the service to avoid edge cases of this with javascript  I guessed what initialized was meant to do  feel free to correct me if I guessed wrong

User · Answer

For shorter JavaScript-Code use this   myApp service  userService         q   function  q        this initialized    q when        this user           access  false            this isAuthenticated   function           this user             first name   First           last name   Last           email   email address com           access   institution                 return this initialized                   You know that you loose the binding to userService user by overwriting it with a new object instead of setting only the objects properties   Here is what I mean as a example of my plnkr co example code  Working example  http   plnkr co edit zXVcmRKT1TmiBCDL4GsC p preview    angular module  myApp       service  userService           http     q     rootScope     location   function   http   q   rootScope   location        this initialized    q when null       this user             access  false            this isAuthenticated   function              this user first name    First           this user last name    Last           this user email    email address com           this user access    institution           return this initialized               angular module  myApp   controller  myCtrl      scope    userService   function   scope  userService         scope user   userService user       scope callUserService   function              userService isAuthenticated   then function                   scope thencalled   true

User · Answer

To return a resolved promise  you can use   return  q defer   resolve      If you need to resolve something or return data   return  q defer   resolve function         var data      return data

User · Answer

From your service method   function serviceMethod         return  timeout function             return               property   value                    1000       And in your controller   serviceName      serviceMethod        then function data             handle the success condition here         var x   data property

User · Answer

How to simply return a pre-resolved promise in AngularJS Resolved promise  return  q when  someValue          angularjs 1 2  return  q resolve  someValue       angularjs 1 4   alias to  when  to match ES6  Rejected promise  return  q reject  someValue

[javascript] How to return a resolved promise from an AngularJS Service using $q?

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