Medium article: SLC part 1 - Validation

Validation.swift

enum Validation<Validated> {
    case valid(Validated)
    case invalid(errorMessage: String)
    var asValidated: Validated? {
        switch self {
        case .valid(let validated): return validated
        default: return nil
        }
    }

    var isValid: Bool {
        return asValidated != nil
    }
}