正在保存的对象

customer: irelyn - items: ["Chicken Bacon Ranch", "BLT"] - total price: 17.30

IM收到错误：

The operation couldn’t be completed. (FirebaseFirestoreSwift.FirestoreEncodingError error 0.)

这是我的密码：

//function to save the order 

    func saveItem(item: Order, completion: @escaping (Error?) -> ()) {
        
    
            let db = Firestore.firestore()
            let encoder = JSONEncoder()
            do {
                let data = try encoder.encode(item)
                let dictionary = try JSONSerialization.jsonObject(with: data, options: []) as? [String : Any] ?? [:]
                db.collection("items").addDocument(data: dictionary) { (error) in
                    completion(error)
                }
            } catch {
                completion(error)
            }
        }
    
}

我的“订单”对象模型：

struct Order: Identifiable, Codable {
    
    @DocumentID var id: String?
    let customer: String
    let total: String
    let orderItems: [String]
    
}

//the menuitem objects -> im storing the name into an array for all the items being ordered in the object above 

struct MenuItem: Identifiable, Codable {
    
    var id: String?
    var name: String
    var description: String
    var price: Double
}

View Code: 
Button {
    
    //store the menu items
    let array: [MenuItem] = appVM.myCart
    let menuItems: [String]  = array.map { $0.name }
    
    let formatter = NumberFormatter()
    formatter.minimumFractionDigits = 2
    formatter.maximumFractionDigits = 2
    
    let price = appVM.totalAmount
    let orderTotal = formatter.string(for: price) ?? ""
    let user = loginVM.currentUser?.fullName
    
    //store the new order with total, name, and order
    let newOrder = Order(customer: user ?? "",total: orderTotal, orderItems: menuItems)
    
    print("customer: \(newOrder.customer) - items: \(newOrder.orderItems) - total price: \(newOrder.total)")
    
    
    appVM.saveItem(item: newOrder) { (error) in
        if let error = error {
            print(error.localizedDescription)
        } else {
            print("Success")
        }
    }
    
} label: {
    
    Text("Place My Order!")
        .bold()
        .padding()
        .frame(maxWidth: .infinity)
        .background(Color.white)
        .cornerRadius(30)
        .padding(.horizontal)
        .foregroundColor(.orange)
    
}

数据都是正确创建的，如果数据不能正常工作，它只是上传。尝试了许多解决方案，没有工作。帮助将不胜感激！