LocalizedError.md

LocalizaedError

오류에 대한 발생 이유를 설명하는 오류 프로토콜
해당 프로토콜을 준수하고, 아래 computed property를 정의하면 호출부에서 .localizedDescription 사용이 가능

extension LocalizedError {

    /// A localized message describing what error occurred.
    public var errorDescription: String? { get }

    /// A localized message describing the reason for the failure.
    public var failureReason: String? { get }

    /// A localized message describing how one might recover from the failure.
    public var recoverySuggestion: String? { get }

    /// A localized message providing "help" text if the user requests help.
    public var helpAnchor: String? { get }
}

프로젝트에 적용하여 실습

enum Errors: LocalizedError {
    case invalidUserInput
    case failOfFormatToString
    
    var errorDescription: String? {
        return NSLocalizedString("Error Type: \(self)", comment: "")
    }
}

guard let totalSpend = numberFormatter.string(for: totalLeadTime) else {
            return Errors.failOfFormatToString.localizedDescription
        }

🌐 Reference Site

[iOS - swift] Error, LocalizedError, localizedDescription 개념
LocalizedError | Apple Developer Documentation