Troubles using promise with AngularJS

Question

I'm currently working on an application based on node.js, the server side seems to be running properly but I'm having hard times with the public side.

I'm trying to use a promise with AngularJS in a controller. Here's my code :

var userId;
var userEmail = "somethingICanRecognizeInCaseItDoesntChange";

function getUserInfos(){
    var deferred = $q.defer();
    if(SessionStorageService.get('token')){
        Auth.isAlive().success(function(user){
            $scope.user = user;
            console.log("user :", user);
            console.log("user email :", user.email);
            deferred.resolve(user.email);
        });
    }
    else {
        $scope.user = {};
        deferred.resolve([]);
    }
    return deferred.promise;
}

userEmail = getUserInfos();
console.log("result :", userEmail);

I thought that result in console would be the same as user email, but it's not. Here's the console log :

result : Object { $$state: Object }
user : Object { firstName: "super", lastName: "admin", email: "a", isSuperAdmin: true, _ts: "2016-05-03T11:17:06.943Z" } website-ranking.js:41:21
user email : a

Here's a screenshot of what I get by clicking on Object in my browser console :

The problem is, whatever I try, I never have a as result. I tried things like getUserInfos().$$state, getUserInfos().$$state.value, getUserInfos().$$state.Object, getUserInfos().Object, getUserInfos().Object.value and none of these worked.

What do I miss here ? Am I using promise in a wrong way ? Am I forgetting something ?

Please don't hesitate to tell me if this question can be improved, I'll gladly add code, or any informations you may need to help me solve my problem.

Edit : the thing is, I already used most of the code elsewhere, it's only since I added promise that I'm a bit lost. Here for example, I use the Auth.isAlive() without any problem :

function getUserInfos(cb){
            if(SessionStorageService.get('token')){
                Auth.isAlive().success(function(user){
                    $scope.user = user;
                    cb();
                });
            }
            else {
                $scope.user = {};
                cb();
            }
        }

The $scope.user is modified and usable further in the application with no issue.

As the question has been tagged as possible duplicate, I'd like to explain a bite more : I know why I'm using a promise, and I think I understood the differents issues with async in javascript. Here my problem is that my code doesn't work and I can't understand why, though I already successfully used promises in the past. I'm not asking how to get a response from async call, but a little help understand where I went wrong while writting code. If you still think that's a duplicate, let me know in comments and I'll deal with it, it's possible that I missed something in the link provided.

Answer 1

Because your method getUserInfos() returns a promise, you're able to do this:

var userId;
var userEmail = "somethingICanRecognizeInCaseItDoesntChange";

function getUserInfos(){
    var deferred = $q.defer();
    if(SessionStorageService.get('token')){
        Auth.isAlive().success(function(user){
            $scope.user = user;
            console.log("user :", user);
            console.log("user email :", user.email);
            deferred.resolve(user.email);
        });
    }
    else {
        $scope.user = {};
        deferred.resolve([]);
    }
    return deferred.promise;
}

getUserInfos().then(function(_email){
  userEmail = _email;
  console.log("result :", userEmail);
});