Using Firebase reauthenticate

Question

I'll appreciate assistance with how to reauthenticate a user in Firebase. I wonder if it makes any sense adding all these great features if the documentation doesn't explain how to use it:

Currently, this is what I'm trying, and it ain't working. Errors as cannot read property 'credential' of undefined

In constructor:

  constructor(@Inject(FirebaseApp) firebaseApp: any) {
    this.auth = firebaseApp.auth();
    console.log(this.auth);
  }

then the function

changePassword(passwordData) {
    if(passwordData.valid) {
      console.log(passwordData.value);
      // let us reauthenticate first irrespective of how long
      // user's been logged in!

      const user = this.auth.currentUser;
      const credential = this.auth.EmailAuthProvider.credential(user.email, passwordData.value.oldpassword);
      console.log(credential);
      this.auth.reauthenticate(credential)
        .then((_) => {
          console.log('User reauthenticated');
          this.auth.updatePassword(passwordData.value.newpassword)
            .then((_) => {
              console.log('Password changed');
            })
            .catch((error) => {
              console.log(error);
            })
        })
        .catch((error) => {
          console.log(error);
        })
    }
  }

Answer 1

The reauthenticate() method is called on a firebase.User, not on firebase.auth.Auth itself.

var user = firebase.app.auth().currentUser;
var credentials = firebase.auth.EmailAuthProvider.credential('puf@firebaseui.com', 'firebase');
user.reauthenticate(credentials);

---

Update (July 2017):

There are some breaking change in the 4.0 version of the Firebase Web SDK. From the release notes:

BREAKING: firebase.User.prototype.reauthenticate has been removed in favor of firebase.User.prototype.reauthenticateWithCredential.

As far as I can tell the reauthenticateWithCredentialis a drop-in replacement for the old method.

Answer 2

Here's some code that enabled users to (a) reauthenticate in Firebase and (b) change their passwords after reauthenticating for me. I researched for about an hour while writing this, so hopefully it saves someone a minute.

Wrote in VueJS:

changePassword() {
            let self = this; // i use "self" to get around scope issues
            var user = firebase.auth().currentUser;
            var credential = firebase.auth.EmailAuthProvider.credential(
                this.$store.state.userId, // references the user's email address
                this.oldPassword
            );

            user.reauthenticateWithCredential(credential)
                .then(function() {
                    // User re-authenticated.
                    user.updatePassword(self.newPassword) 
                        .then(function() {
                            console.log("Password update successful!");
                        })
                        .catch(function(error) {
                            console.log(
                                "An error occurred while changing the password:",
                                error
                            );
                        });
                })
                .catch(function(error) {
                    console.log("Some kinda bug: ", error);
                    // An error happened.
                });

Answer 3

Slight changes as of May 2019, see more details here. Code is as follows:

var user = firebase.auth().currentUser;
var credential = firebase.auth.EmailAuthProvider.credential(user.email, password);

// Prompt the user to re-provide their sign-in credentials
return user.reauthenticateWithCredential(credential);

Answer 4

Call changeEmail("new email","password") in onPressed directly to update the user email with no reauthentication required error

RaisedButton(
  onPressed: () {
    changeEmail(_emailController.text, _passwordController.text);
  }              

 Future<void> changeEmail(String email, String password) async {
   User user = await FirebaseAuth.instance.currentUser;
  print(email);
  print(password);
  try {
    try {
      var authResult = await user.reauthenticateWithCredential(
        EmailAuthProvider.getCredential(
          email: user.email,
          password: password,
        ),
      );
      user.updateEmail(email).then((_) {
        print("Succesfull changed email");
        _backthrow();
      }).catchError((error) {
        showAlertDialog(context, error.message);
        print("email can't be changed" + error.toString());
      });
      return null;
    } catch (e) {
      print("2");
    }
  } catch (e) {
    print(e.message);
    showAlertDialog(context, e.message);
  }
}

Answer 5

This is how I re-authenticate a user in Firebase:

import { getAuth, EmailAuthProvider, reauthenticateWithCredential } from "firebase/auth";

const auth = getAuth()

const reauthenticateUser = async (email, password) => {
  const user = auth.currentUser;
  try {
    const credential = EmailAuthProvider.credential(email, password);
    await reauthenticateWithCredential(user, credential)
  } catch (error) {
    Alert.alert("Error", "The email or password is incorrect. Please try again.")
  }
}

Answer 6

Hers a full example how to reauthenticate with Firebase

var pass = "abcdefg";
var user = firebase.auth().currentUser;
var credential = firebase.auth.EmailAuthProvider.credential(user.email, pass);

user.reauthenticateWithCredential(credential).then(() => {
    console.log("Its good!");
}).catch((error) => {
    console.log(error);
});

Answer 7

Since 2021: If you use Firebase JS API 9.x (the tree shakable version) this is the most recent way:

https://cloud.google.com/identity-platform/docs/web/reauth

With credentials

import { getAuth, reauthenticateWithCredential } from "firebase/auth";

const auth = getAuth();
const user = auth.currentUser;

// todo for you: prompt the user to re-provide their sign-in credentials
const credential = promptForCredentials();

reauthenticateWithCredential(user, credential).then(() => {
  // ...
}).catch((error) => {
  // ...
});

With popup

import { getAuth, reauthenticateWithPopup, OAuthProvider } from "firebase/auth";

const auth = getAuth();
// todo for you: change to appropriate provider
const provider = new OAuthProvider('apple.com');

reauthenticateWithPopup(auth.currentUser, provider)
  .then((result) => {
    // ...
  })
  .catch((error) => {
    // ...
  });

Answer 8

I was getting that re-authentication error auth/requires-recent-login when saving the primary email.
I couldn't figure out how to implement that poorly documented reauthenticateWithCredential(credential) method, so, I simply logged-out the user and redirected to login page. It's a hack but It works like charm!

firebase.auth().signOut();