[cwbrandsma]

With Swift, that assumes that the function being called reports the error in the first place. Very few functions do.

Cast a large double to an int -- crash. How do you catch that error? You can't. You have to make sure it never happens yourself. The UserDefaults is another great one. All sorts of ways that it can crash your app, none of them can be caught or handled. Your app just crashes. My advice: convert all your object to a text string (like json) and store that. Do NOT store a dictionary representation.