blog

1.lying-function.swift

func submitButtonPressed {
  showLoadingWheel()
  defer { hideLoadingWheel() }
  guard let username = validateInput() else {
    showErrorAlert()
    return
  }
  let payload = ["username": username];
  webService.sendPOSTRequest(withPayload: payload)
}

func validateInput -> String? {
  guard let username = self.usernameField.text else { return nil }
  let trimmedUsername = username.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
  return trimmedUsername.length > 0 ? trimmedUsername : nil
}