I'm trying to use firebase admin SDK in order to link the Email/Password sign-in method.

Based on firebase documentation we can links user to a specific provider https://firebase.google.com/docs/reference/admin/node/firebase-admin.auth.updaterequest.md#updaterequestprovidertolink

based on that I'm using :

await admin
           .auth()
           .updateUser(user.uid, {
                providerToLink: {
                    uid: user.email,
                    email: user.email,
                    displayName: user.displayName,
                    providerId: 'password',
                },
            })
            .catch((error: any) => {
                console.error(`${error}`);
            });

It should link the Email/Password sign-in method to a specific user, but instead of that it's returning error with

• code = auth/invalid-provider-id
• message = The providerId must be a valid supported provider identifier string.

It's working as expected when the providerId equal to facebook.com or google.com

Question

Is there is another providerId I should use in order to link the Email/Password sign-in method ?

Is there another approach I should use in order to link the Email/Password sign-in method ?

Node version : 12

firebase-admin : 9.12.0