lu4nm3

case class EmailAddress(emailAddress: String)

lu4nm3

scala> EmailClient.sendEmail(from = EmailAddress("[email protected]"), to = EmailAddress("[email protected]"))(
  """
  Hello,

  Hope you're doing well!

  Best,
  Luis
  """
)

lu4nm3

scala> EmailAddress("@example.com")
res0: EmailAddress = EmailAddress(@example.com)

lu4nm3

object EmailAddress {

  // Regex that captures the "official" format standard (RFC 5322) that email addresses must adhere to
  private val EmailRegex = """(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])""".r

  private def isValidAddress(emailAddress: String): Boolean = {
    EmailRegex.findAllMatchIn(emailAddress).length == 1
  }

  def apply(emailAddress: String): EmailAddress = {

lu4nm3

scala> EmailAddress("@example.com")
java.lang.IllegalArgumentException: requirement failed: Invalid email address
  at scala.Predef$.require(Predef.scala:277)
  at EmailAddress$.apply(<pastie>:23)
  ... 36 elided

lu4nm3

def apply(emailAddress: String): Either[String, EmailAddress] = {
  if (isValidAddress(emailAddress)) {
    Right(new EmailAddress(emailAddress))
  } else {
    Left("Invalid email address")
  }
}

lu4nm3

scala> EmailAddress("@example.com")
res0: Either[String,EmailAddress] = Left(Invalid email address)

lu4nm3

scala> val emailAddress = EmailAddress("[email protected]")
emailAddress: Either[String,EmailAddress] = Right(EmailAddress([email protected]))

scala> emailAddress.map(_.copy(emailAddress = "@example.com"))
res0: scala.util.Either[String,EmailAddress] = Right(EmailAddress(@example.com))

lu4nm3

case class EmailAddress(emailAddress: String) {
  def copy(emailAddress: String = emailAddress): Either[String, EmailAddress] = {
    EmailAddress(emailAddress)
  }
}

lu4nm3

scala> EmailAddress("[email protected]").map(_.copy(emailAddress = "@example.com"))
res0: scala.util.Either[String,Either[String,EmailAddress]] = Right(Left(Invalid email address))

scala> for {
  |   e1 <- EmailAddress("[email protected]")
  |   e2 <- e1.copy(emailAddress = "@example.com")
  | } yield e2
res1: scala.util.Either[String,EmailAddress] = Left(Invalid email address)