Result promise being processed before it executed on Ionic 2 Facebook login - ionic-framework

Question

I have an Ionic 2 application running the following code on an Angular 2 service:
signInWithFacebook(): firebase.Promise<any>
{
if (this.platform.is('cordova'))
{
console.log('Running on cordova...');
Facebook.login(['email', 'public_profile']).then(res =>
{
const facebookCredential = firebase.auth.FacebookAuthProvider.credential(res.authResponse.accessToken);
console.log('credential value', facebookCredential);
var temp = firebase.auth().signInWithCredential(facebookCredential);
console.log('temp value: ', temp);
return temp;
});
}
else
{
return this.auth$.login({
provider: AuthProviders.Facebook,
method: AuthMethods.Popup
});
}
}
Then on my login component page I call it like this, on a login button:
pubic doFacebookLogin(): void
{
var temp = this.userDataService.signInWithFacebook()
.then(() =>
{
console.log("Passed here! [1]");
this.onSignInSuccess();
console.log("Passed here! [2]");
});
}
My console logs the following when I click the button:
Running on cordova...
main.js:46695 TypeError: Cannot read property 'then' of undefined
at LoginPage.doFacebookLogin (main.js:50920).....
credential value Lf {accessToken: "xxxxxx", provider: "facebook.com"}
temp value: I {F: 0, ka: undefined, o: I, fa: null, Ma: null…}
The flow I'm expecting is this:
call to the doFacebookLogin() method
call to the service.signInWithFacebook() method
Console logs 'Running on cordova...'
step [1] waits for the return promisse of [2]
call to Facebook.login(['email', 'public_profile'])
when the login on [4] is concluded, it calls the firebase.auth().signInWithCredential() method, which returns a promise too
Console logs 'credential value' and 'temp value'
the result promise of [5] is then returned on the service.signInWithFacebook() function
the doFacebookLogin() function finally processes the promise returned on [6] and execute onSignInSuccess()
But from the console logs we can see that it's logging 'Running on cordova', then we get an exception on the .then call of the first funcion (so the facebook login result promise was not yet processed (so the return promise doesn't exist), and after this the facebook login is processed (and now it exists, but the other function already tried to process it, generating the exception).
What am I missing with these promises?

Answer 1

It looks like you are just missing a return.
return Facebook.login(....).then(...);