import * as Firebase from 'firebase'

const auth = Firebase.auth()
const email = someEmail
const password = somePassword

try {
  const credential = await auth.createUserWithEmailAndPassword(email, password)
  const user = credential.user
  if (user === null) {
    throw new Error(
      `creating user for authentication was success, but nobody is logging in. something wrong! credential: ${credential}`
    )
  }

  await user.updateProfile({ displayName: 'Haskell' })  // !
  await user.sendEmailVerification()
} catch (e) {
  if (e instanceof Error && /The email address is already in use by another account./.test(e.message)) {
    throw new Error(`メールアドレス「${account.email}」は既に使用されています。`)
  }
  throw new Error(e)
}