function mergeAccounts()

in auth-next/link-multiple-accounts.js [113:158]

• 26 lines of code
• 1 McCabe index (conditional complexity)

function mergeAccounts(newCredential) {
  // [START auth_merge_accounts]
  const { getAuth, signInWithCredential, linkWithCredential, OAuthProvider } = require("firebase/auth");

  // The implementation of how you store your user data depends on your application
  const repo = new MyUserDataRepo();

  // Get reference to the currently signed-in user
  const auth = getAuth();
  const prevUser = auth.currentUser;

  // Get the data which you will want to merge. This should be done now
  // while the app is still signed in as this user.
  const prevUserData = repo.get(prevUser);

  // Delete the user's data now, we will restore it if the merge fails
  repo.delete(prevUser);

  // Sign in user with the account you want to link to
  signInWithCredential(auth, newCredential).then((result) => {
    console.log("Sign In Success", result);
    const currentUser = result.user;
    const currentUserData = repo.get(currentUser);

    // Merge prevUser and currentUser data stored in Firebase.
    // Note: How you handle this is specific to your application
    const mergedData = repo.merge(prevUserData, currentUserData);

    const credential = OAuthProvider.credentialFromResult(result);
    return linkWithCredential(prevUser, credential)
      .then((linkResult) => {
        // Sign in with the newly linked credential
        const linkCredential = OAuthProvider.credentialFromResult(linkResult);
        return signInWithCredential(auth, linkCredential);
      })
      .then((signInResult) => {
        // Save the merged data to the new user
        repo.set(signInResult.user, mergedData);
      });
  }).catch((error) => {
    // If there are errors we want to undo the data merge/deletion
    console.log("Sign In Error", error);
    repo.set(prevUser, prevUserData);
  });
  // [END auth_merge_accounts]
}