swift guard.swift

Posted 2021-05-19

struct Person {
    let name: String
    var age: Int
}

struct PersonViewModel {
    var name: String?
    var age: String?

    enum InputError: ErrorType {
        case InputMissing
        case AgeIncorrect
    }

    func createPerson() throws -> Person {
        guard let age = age, let name = name
            where name.characters.count > 0 && age.characters.count > 0 else {
                throw InputError.InputMissing
        }

        guard let ageFormatted = Int(age) else {
            throw InputError.AgeIncorrect
        }

        return Person(name: name, age: ageFormatted)
    }
}


// usage
do {
    let person = try personViewModel.createPerson()
    print("Success! Person created. \(person)")
} catch PersonViewModel.InputError.InputMissing {
    print("Input missing!")
} catch PersonViewModel.InputError.AgeIncorrect {
    print("Age Incorrect!")
} catch {
    print("Something went wrong, please try again!")
}