Assigning one of many values to object's property

I want to parse a firebase auth credentials object which is differently formatted for various sign in methods.

For example for password sign up the data I want are in credentials directly, but for facebook or google login the data I want are in credentials.user

So I have this function going:

parseCredentials(credentials: any): User {
    const parsedCredentials: User = {
      displayName: credentials.displayName || credentials.user.displayName,
      email: credentials.email || credentials.user.email,
      emailVerified: credentials.emailVerified || credentials.user.emailVerified,
      uid: credentials.uid || credentials.user.uid
    };
    return parsedCredentials;
  }

As you can see I use the function to return a new User object based on the credentials passed to the fn, because I don't need unnecessary information in the User object.

The problem is when I sing up with email-password I get error: credentials.user is undefined

I think is something wrong with the || operators. It seems that credentials.user is undefined (because the user property does not exist on credentials object when signing up with email-password).

But thats why I used the || operator. Struggling with this for a while but I can't figure out. Hope you can give some help. Thanks.