Firebase Re-authentication & email Linking for Phone-Authenticated Users - node.js

Question

When users sign up, they use Phone Auth. After using the app for a while, they are advised to link an (email & password) to their existing account.
The linking process fails because of the error (auth/requires-recent-login.) My code follows.
// The following generates the error: [auth/requires-recent-login] This operation is sensitive and requires recent authentication. Log in again before retrying this request.
const emailCredential = firebase.auth.EmailAuthProvider.credential(state.email, state.password);
const newCredential = await firebase.auth().currentUser.linkWithCredential(emailCredential);
To fix this error, I understand that I need to call reauthenticateWithCredential() before linking. However, I don't want to ask the user to log in again (receive & enter a verification code.) Is this at all possible?
I tried passing the result of currentUser.getIdToken(true) to PhoneAuthProvider.credential() I am not sure if this is right. Anyway, it generated an error (Cannot create PhoneAuthCredntial without either verificationProof, sessionInfo, temporary proof, or enrollment ID.).
My code follows.
// The following works:
const accessToken = await firebase.auth().currentUser.getIdToken(true);
// The following works:
const currentCredential = firebase.auth.PhoneAuthProvider.credential(accessToken);
// The following generates the error: Cannot create PhoneAuthCredential without either verificationProof, sessionInfo, temporary proof, or enrollment ID.
const abc = await firebase.auth().currentUser.reauthenticateWithCredential(currentCredential);
// The following is never reached:
const emailCredential = firebase.auth.EmailAuthProvider.credential(state.email, state.password);
const newCredential = await firebase.auth().currentUser.linkWithCredential(emailCredential);
Thank you for your effort and time to help me...

Answer 1

Important Information:
firebase.auth().currentUser.reauthenticateWithCredential(credential) requires the attribute credential
For users, who logged in using a Phone Number, I could not find a way to get this credential when required. By the way, it is possible to get it for users, who logged in using other providers, e.g. Facebook.
However, for users, who log in using a phone number, it is possible to get this credential during the login process. Check https://firebase.google.com/docs/auth/web/phone-auth.
So, I decided to save the credential for the user on their device during the login process. I am using Redux and Redux-Persist for that.
My code after fixing it.
// This is an extract from the login script:
firebase.auth().signInWithPhoneNumber(phoneNo)
.then(confirmResult => {
dispatch({ type: "PhoneNo_accepted", payload: { confirmResult: confirmResult } });
})
.catch(error => {
dispatch({ type: "display_message", payload: { messageText: `Phone Number Error: ${error.message}` } });
});
// Change#1. The following statement is a NEW step, which I added to get the credential during the login process.
const credential = firebase.auth.PhoneAuthProvider.credential(state.confirmResult.verificationId, state.codeInput);
state.confirmResult.confirm(state.codeInput)
.then( (user) => {
// Change#2. The following function would save the credential to the app's state, e.g. using Redux
_onAuthComplete(user, credential);
})
.catch( error => {
dispatch({ type: "display_message", payload: { messageText: `Verification Code Error: ${error.message}` } });
});
// // //
// This is an extract from the linking script:
// Change#3. props.credential is the credential, which was saved to the app's state.
await firebase.auth().currentUser.reauthenticateWithCredential(props.credential);
const emailCredential = firebase.auth.EmailAuthProvider.credential(state.email, state.password);
const newCredential = await firebase.auth().currentUser.linkWithCredential(emailCredential);