Angular "Cannot read property 'then' of undefined" with promise

Question

I am stuck on why my promises aren't working. From the other articles I have looked at, I think I am doing it correctly. Here is the code I have currently:

Factory code

factory.isLoggedIn = function() {
  $http.get('/api/v1/fitbit/auth')
      .success((data) => {
           return data.status;
       })
       .error((error) => {
           console.log('Error: ' + error);
       });
}

Controller code

    $scope.fitbitAuth = function() {
        FitbitFactory.isLoggedIn()
            .then(
                function(data) {
                    $scope.fitbitStatus = data;
                },
                function(errorData) {
                    console.log(errorData);
                });
        return $scope.fitbitStatus;
    };

From my understanding of promises, the return $scope.fitbitStatus should be populating the $scope.fitbitAuth, but it isn't. I am also returning a boolean in the Factory, which should be populating $scope.fitbitStatus.

add return statement before $http in factory.isLoggedIn

vijay
– vijay

2016-11-25 20:20:47 +00:00
Commented Nov 25, 2016 at 20:20 — vijay
– vijay, Commented Nov 25, 2016 at 20:20
and get rid of success and error in your factory.

user4164128
– user4164128

2016-11-25 20:21:52 +00:00
Commented Nov 25, 2016 at 20:21 — user4164128
– user4164128, Commented Nov 25, 2016 at 20:21

baao · Accepted Answer · 2016-11-25 20:48:41Z

2

You have to return something (the promise), or it is undefined.

Factory code:

factory.isLoggedIn = function() {
  return $http.get('/api/v1/fitbit/auth');
}

Controller code:

$scope.fitbitAuth = function() {
    return FitbitFactory.isLoggedIn()
        .then(
            function(data) {
                $scope.fitbitStatus = data;
            },
            function(errorData) {
                console.log(errorData);
            });

};

The complete success/error block in your factory is not necessary and should be removed. I'm also unsure why you return $scope.fitbitStatus; as it is undefined at the time of return.

Edit: Edited the answer to actually return the promise.

edited Nov 25, 2016 at 20:48

answered Nov 25, 2016 at 20:27

baao

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3 Comments

2b2a Over a year ago

I returned $scope.fitbitStatus because some of the other forums I was looking at recommended returning the promise. I may, and probably am, mistaken in how I implemented it though.

baao Over a year ago

You are not returning a promise, but something that is undefined at the time you are returning. I edited the answer. @2b2a

baao Over a year ago

@2b2a see where I moved the return in the controller code. Now the promise is returned. What you were returning will be undefined at the time you were returning

Pankaj Parkar · Accepted Answer · 2016-11-25 20:31:22Z

1

Currently you haven't return anything from isLoggedIn factory method and you are calling .then method over it.

To make it working return $http promiseobject from service method. In your case you could simply return$http.getmethod call which return promise object itself and then you can easily chain them up by callingFitbitFactory.isLoggedIn().then`

factory.isLoggedIn = function() {
  return $http.get('/api/v1/fitbit/auth');
}

edited Nov 25, 2016 at 20:31

answered Nov 25, 2016 at 20:25

Pankaj Parkar

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