iOS Error Handling in Swift Error Handling Throwing Errors

Error Handling Challenge Task 2 What is the single member? How can I have an error for invalidData if I have no data?

Here is what I am trying:

enum BookError: Error { case incorrectTitle }

func lend(book: String?) throws { guard let book = book else { throw BookError.incorrectTitle } }

error.swift
enum BookError: Error {
  case incorrectTitle
}

func lend(book: String?) throws  {
    guard let book = book else {
        throw BookError.incorrectTitle
    }
}

1 Answer

Nichlas Kondrup
Nichlas Kondrup
17,746 Points

The function shouldn't have any parameters. The function should simply throw the incorrectTitle error. The incorrectTitle error is referred as the single member because it is the only member in the enum.

enum BookError: Error {
  case incorrectTitle
}

func lend() throws {
  throw BookError.incorrectTitle
}