Validators6.swift

protocol ValidatorConvertible {
    func validated(_ value: String?) throws -> String
}

enum ValidatorType {
    case email
    case password
    case username
    case projectIdentifier
    case requiredField(field: String)
    case age
}

enum VaildatorFactory {
    static func validatorFor(type: ValidatorType) -> ValidatorConvertible {
        switch type {
        case .email: return EmailValidator()
        case .password: return PasswordValidator()
        case .username: return UserNameValidator()
        case .projectIdentifier: return ProjectIdentifierValidator()
        case .requiredField(let fieldName): return RequiredFieldValidator(fieldName)
        case .age: return AgeValidator()
        }
    }
}