Fulfill the promise in AngularJS and assign it to a different factory

Question

Fulfill the promise in AngularJS and assign it to a different factory

Presenting my factory below:

.factory('UserData', ['User', '$q', function(User, $q) {
    var deferred = $q.defer();

    return {
        user: null,
        get: function() {
            var _this = this;
            _this.user = User.get();
            deferred.resolve(User.get());
            return deferred.promise();
        }

    };

}]);

In the User factory, there is some relevant data available which can be retrieved using User.get(). My goal is to retrieve this data and assign it to user: null in my UserData factory.

javascript angularjs angular-promise

Answer 1

Answer №1

Solution:

.service('UserData', ['User', '$q', function(User, $q) {
   var _service = {};

   _service.user = null;

   /* returns a promise that resolves to user value */
   _service.get = function() {
     // return cached user as a resolved promise
     if (_service.user) return $q.resolve(_service.user);

     return User.get().then(function(user) { // chain User.get() promise
       return _service.user = user; // cache user value in _service.user
     });
   };

   return _service;
}]);

It seems like you might prefer using a cached version (just return value if service.user is already populated). You can simply remove the caching part if this isn't necessary.

Additionally, consider whether or not you want to expose the user variable as part of the service. If not, you may want to declare it as a variable instead and modify references to _service.user to conceal internal implementation details.

Answer 2

Solution:

.service('UserData', ['User', '$q', function(User, $q) {
   var _service = {};

   _service.user = null;

   /* returns a promise that resolves to user value */
   _service.get = function() {
     // return cached user as a resolved promise
     if (_service.user) return $q.resolve(_service.user);

     return User.get().then(function(user) { // chain User.get() promise
       return _service.user = user; // cache user value in _service.user
     });
   };

   return _service;
}]);

It seems like you might prefer using a cached version (just return value if service.user is already populated). You can simply remove the caching part if this isn't necessary.

Additionally, consider whether or not you want to expose the user variable as part of the service. If not, you may want to declare it as a variable instead and modify references to _service.user to conceal internal implementation details.

Fulfill the promise in AngularJS and assign it to a different factory

Answer №1

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