Using Firebase reauthenticate

问题

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);
        })
    }
  }

回答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.

回答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.
                });

来源：https://stackoverflow.com/questions/39872885/using-firebase-reauthenticate