Сохранение модели Firestore с @DocumentID в UserDefaults в Swift

Попробуйте использовать пользовательскую функцию кодирования и пользовательскую функцию инициализации (от :)

• Пользовательская функция кодирования, которая кодирует свойство DocumentID с помощью Firestore.Encoder
• Пользовательская функция init(from:), которая декодирует свойство DocumentID с помощью Firestore.Decoder

struct DeviceModel: Identifiable, Codable, Hashable {
    @DocumentID var id: String?
    var fcmToken: String
    var userId: String
    @ServerTimestamp var expiresOn: Timestamp?
    
    enum CodingKeys: String, CodingKey {
        case id
        case fcmToken = "token"
        case expiresOn = "expires_on"
        case userId = "user_id"
    }
    
    init(id: String? = nil,
         fcmToken: String,
         userId: String,
         expiresOn: Timestamp? = Timestamp()) {
        self.id = id
        self.fcmToken = fcmToken
        self.userId = userId
        self.expiresOn = expiresOn
    }
    
    // Custom init(from:) function that decodes the id property using the Firestore.Decoder
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        fcmToken = try container.decode(String.self, forKey: .fcmToken)
        userId = try container.decode(String.self, forKey: .userId)
        expiresOn = try container.decode(Timestamp?.self, forKey: .expiresOn)
        
        // Decode the DocumentID property using the Firestore.Decoder
        if let idContainer = try? decoder.container(keyedBy: CodingKeys.self),
           let id = try? idContainer.decode(String.self, forKey: .id) {
            self.id = id
        }
    }
    
    // Custom encode function that encodes the DocumentID property using the Firestore.Encoder
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(fcmToken, forKey: .fcmToken)
        try container.encode(userId, forKey: .userId)
        try container.encode(expiresOn, forKey: .expiresOn)
        
        // Encode the DocumentID property using the Firestore.Encoder
        if let id = id {
            let firestoreEncoder = Firestore.Encoder()
            let something = try firestoreEncoder.encode(["id":id])
            
            if let mapId = something["id"] as? String {
                try container.encode(mapId, forKey: .id)
            }
        }
    }
}