Swift reverse guard issues

Question

I have closure that may return an error. It look like:

session.dataTask(with: url) { (data, response, error) in

Next I want to handle error. I want to use guard statement for unwrap error, and if it exist, that show alert and return function. But how could I perform something like

guard !(let error = error) else { return }

I can't. I can check for nil and then unwrap error again, but that look kind of ugly. Or I can use if let unwrapping, but for error checking I prefer guard. So, is there any way to nicely write following?

guard !(let error = error) else { return }

Answer 1

Don't fight the framework.

• If you want to use the unwrapped optional within the braces use if let

  if let error = error {
     print(error)
     return
  }
  

• If you want to use the unwrapped optional after the braces use guard let

  guard let error = error else {
     return
  }
  print(error)
  

• If the (unwrapped) content of error doesn't matter just check for nil

  guard error == nil else { ... 
  if error == nil { ...