Get Firebase User.ProviderID on auth/wrong-password when using signInWithEmailAndPassword - firebase

Question

I have an Application that uses Firebase for Authentification.
I allow users to sign in with either Google/Facebook/Twitter or using an Email and Password.
Additionally I have activated within Firebase that Users can only create one account per email.
I want to cover the Following case:
A users signs up with facebook and gets a user account created with their facebook email (e.G. facebookuser#gmail.com).
A few days later the user comes back to the app, but forgot that he signed up using facebook and tries loging in with their email adress facebookuser#gmail.com and their usual password instead.
The firebase.auth().signInWithEmailAndPassword(email, password) method throws an auth/wrong-password error, as no password was given using the facebook login method but the email does exist.
Instead of showing a useless "Wrong password or the account corresponding to the email does not have a password set." error I would like to check instead which provider was used for signing up and reminding the user to sign in with the provider instead.
Unfortunately there doesn't seem to exist a method to get the User.ProviderID for a given email or to understand if the auth/wrong-password error was given because the user typed in a wrong password or if there was no password given in first place as the user signed up with an OAuthProvider instead.

Answer 1

Okay, I have missed the fetchProvidersForEmail method.
Just for Reference: (not the final code I will be using)
Uses signInWithEmailAndPassword to check if a User exists
If it doesn't it creates it using createUserWithEmailAndPassword
If a user exits, it tries to login and catches errors
If the error is auth/wrong-password it checks with fetchProvidersForEmail if the user has used a Provider to sign up
firebase.auth().signInWithEmailAndPassword(email, password).catch(function(error) {
var errorCode = error.code;
var errorMessage = error.message;
// User not found? Create user.
if ( errorCode === 'auth/user-not-found' ) {
firebase.auth().createUserWithEmailAndPassword(email, password).catch(function(error) {
// Handle Errors here.
var errorCode = error.code;
var errorMessage = error.message;
if ( errorCode == 'email-already-in-use' ) {
alert('You already have an account with that email.');
} else if ( errorCode == 'auth/invalid-email' ) {
alert('Please provide a valid email');
} else if ( errorCode == 'auth/weak-password' ) {
alert('The password is too weak.');
} else {
alert(errorMessage);
}
console.log(error);
});
// Wrong Password Error
} else if ( errorCode === 'auth/wrong-password' ) {
// Check if User has signed up with a OAuthProvider
firebase.auth().fetchProvidersForEmail(email).then(function( result ){
// … show OAuthProvider Login Button
});
alert('Wrong password. Please try again');
} else {
alert( errorMessage );
}
console.log( error );
});