Angularjs - how do I set module values in a service?

Question

I have the following services module for an Angular app.

angular.module('rs.services', [])
  .value('uid', null)

  .factory('login', ['$http', 'uid', function($http, uid) {
    return function(user, pass) {
      var p = $http.post('/login', {"user": user, "pass": pass})
        .success(function(data, status, headers, config) {
          // set uid
        })
        .error(function(data, status, headers, config) {
          // do something
        });

      return p;
    }
  }]);

  // a service that uses uid to authenticate the request
  .factory('userPrefs' ['$http', 'uid', function($http, uid) {
    return function() {
      return $http.post('/user/prefs', {"uid": uid});
    }
  }]);

After a user logs in, the login service returns a unique session id and I want to set the module's uid value for other services calls to refer to.

I'm pretty sure the above code won't work because I can't use a value as a dependency in the module's configuration stage. How can I set the uid value in the login service and access it in other services within the module, or if that's not possible how can I make a value that can be set / get by these services?

Answer 1

Values that are primitives are not meant to hold information that changes during the course of your application. You need to either have the UID value be an object or a standard service. As an object:

.value( 'uid', {} );

.factory('userPrefs' ['$http', 'uid', function($http, uid) {
  // ...
  uid.id = response.data.uid;
  // ...
});

You might also want to place all your user-related stuff into a single service instead of three. See this other SO post for more info: https://stackoverflow.com/a/14206567/259038