swift - Firebase sendEmailVerification prior to createUser -

is there way in firebase verify user's email prior adding user database? ultimate goal create signup form user first enters email address, presses "verify email address" button. @ point verification email sent , user follow link within confirm email address. now, when going app, user have continue button, , if the email not verified, user not able register, if contrary, user able register.

how go this? far documentation says must createuser can use currentuser.sendemailverification, obviously, not want create user, before verification. thought using completion block, not sure how work out, because registration have postponed until user presses continue button.

thanks

auth.auth().createuser(withemail: email, password: password, completion: {(user: user?, error) in              if error != nil {                 print(error!)                 return             }              guard let uid = user?.uid else {                 return             }               let ref = database.database().reference(fromurl: "https://project/")             let values = [                 "email": email,                 "username": username,                 "name": name,                 "birthdate": birthdate,                 "phonenumber": phonenumber]              let userreference = ref.child("users").child(uid)             userreference.updatechildvalues(values, withcompletionblock: {(err, ref) in                 if err != nil{                     print(err!)                     return                 }                  print("successfully added user database")             })              let useduserreference = ref.child("users-used").child(username)             useduserreference.setvalue(uid, withcompletionblock: {(err, ref) in                 if err != nil{                     print(err!)                     return                 }                  print("successfully added user cannot used-again list")             })          }) 

you can't firebase auth. user needs created first, because record "container" gives email verification appropriate context user has been verified when respond email.

in app, can check see if particular user account has been verified using emailverified property. allows give end user different experience respect verification.