Home > @firebase/auth > MultiFactorResolver

MultiFactorResolver interface

The class used to facilitate recovery from MultiFactorError when a user needs to provide a second factor to sign in.

Signature:

export interface MultiFactorResolver 

Example

let resolver;
let multiFactorHints;

signInWithEmailAndPassword(auth, email, password)
    .then((result) => {
      // User signed in. No 2nd factor challenge is needed.
    })
    .catch((error) => {
      if (error.code == 'auth/multi-factor-auth-required') {
        resolver = getMultiFactorResolver(auth, error);
        // Show UI to let user select second factor.
        multiFactorHints = resolver.hints;
      } else {
        // Handle other errors.
      }
    });

// The enrolled second factors that can be used to complete
// sign-in are returned in the `MultiFactorResolver.hints` list.
// UI needs to be presented to allow the user to select a second factor
// from that list.

const selectedHint = // ; selected from multiFactorHints
const phoneAuthProvider = new PhoneAuthProvider(auth);
const phoneInfoOptions = {
  multiFactorHint: selectedHint,
  session: resolver.session
};
const verificationId = phoneAuthProvider.verifyPhoneNumber(phoneInfoOptions, appVerifier);
// Store `verificationId` and show UI to let user enter verification code.

// UI to enter verification code and continue.
// Continue button click handler
const phoneAuthCredential = PhoneAuthProvider.credential(verificationId, verificationCode);
const multiFactorAssertion = PhoneMultiFactorGenerator.assertion(phoneAuthCredential);
const userCredential = await resolver.resolveSignIn(multiFactorAssertion);

Properties

Property	Type	Description
hints	MultiFactorInfo[]	The list of hints for the second factors needed to complete the sign-in for the current session.
session	MultiFactorSession	The session identifier for the current sign-in flow, which can be used to complete the second factor sign-in.

Methods

Method	Description
resolveSignIn(assertion)	A helper function to help users complete sign in with a second factor using an MultiFactorAssertion confirming the user successfully completed the second factor challenge.