Hey there! Let's break down how to properly catch all errors when updating a user's email in Firebase after re-authentication, and also fix a small gotcha in your original code.

First off, there's a tiny but critical detail to fix in your code: calling user.updateEmail() directly inside the first .then() will run that method immediately, instead of waiting for the re-authentication promise to resolve. Wrap it in an arrow function to ensure correct execution order:

const user = firebase.auth().currentUser;
const credential = firebase.auth.EmailAuthProvider.credential('my-email@test.com', 'my-password');
user.reauthenticateWithCredential(credential)
  .then(() => user.updateEmail('my-new-email@test.com')) // Use arrow function here
  .then(() => { console.log('Email updated successfully!'); })
  .catch((error) => {
    // Handle all errors from both stages here
    handleAuthError(error);
  });

Now, let's split the possible errors into two categories: errors from the re-authentication stage and errors from the email update stage, along with how to handle each:

1. Common Errors During Re-authentication #

These occur when reauthenticateWithCredential runs:

• auth/wrong-password: The password entered doesn't match the user's current password
• auth/invalid-email: The current email format is invalid
• auth/user-disabled: The user's account has been disabled
• auth/user-not-found: The user account linked to this email no longer exists (even if they were logged in, it might have been deleted)
• auth/too-many-requests: Too many failed attempts triggered Firebase's security limits

2. Common Errors During Email Update #

These occur when updateEmail runs:

• auth/email-already-in-use: The new email is already registered to another user
• auth/invalid-email: The new email format doesn't meet requirements
• auth/requires-recent-login: Even though you re-authenticated, if too much time passed (usually over 5 minutes), Firebase will demand fresh verification (unlikely here, but good to handle)
• auth/user-disabled: The user's account was disabled right after re-authentication
• auth/user-not-found: The user account was deleted right after re-authentication

Example Unified Error Handling Function #

You can create a reusable function to handle all these cases with user-friendly messages:

function handleAuthError(error) {
  switch(error.code) {
    // Re-authentication errors
    case 'auth/wrong-password':
      console.log('Incorrect password, please try again');
      break;
    case 'auth/invalid-email':
      console.log('Invalid email format, please check your input');
      break;
    case 'auth/user-disabled':
      console.log('This account has been disabled, please contact support');
      break;
    case 'auth/user-not-found':
      console.log('This user account no longer exists');
      break;
    case 'auth/too-many-requests':
      console.log('Too many attempts, please try again later');
      break;
    // Email update errors
    case 'auth/email-already-in-use':
      console.log('This email is already registered, please use a different one');
      break;
    case 'auth/requires-recent-login':
      console.log('Please log in again to update your email');
      break;
    default:
      console.log('Failed to update email:', error.message);
  }
}

Key Notes #

• All errors from both stages will flow into the final .catch() block, since any failure in the promise chain triggers the closest catch handler.
• Never skip the arrow function around user.updateEmail()—without it, you'll run into timing issues, like trying to update the email before re-authentication finishes, which will throw an auth/requires-recent-login error even if you meant to re-authenticate first.

内容的提问来源于stack exchange，提问作者Christophe Le Besnerais