While update specific class object value in Array than it update all object value in array

Question

I have class object array in which store product value, when change specific object value than it change in all object value in array. i have used firstIndex method, map method, filter method to update specific object value but still change all object value in array.

Model for Product:

public class NewSellLocalDataModel:Encodable {
    var sessionId:String = ""
    var totalCount:Int = 0
    var currentCount:Int = 0
    var data = newSellData()
    
    enum CodingKeys: String, CodingKey{
        case sessionId = "sellSessionId"
        case totalCount = "totalCount"
        case currentCount = "currentCount"
        case data = "data"
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(sessionId, forKey: .sessionId)
        try container.encode(totalCount, forKey: .totalCount)
        try container.encode(currentCount, forKey: .currentCount)
        try container.encode(data, forKey: .data)
    }
}

public class newSellData:Encodable {
    var spu:String = ""
    var imagesAndVideo:[String] = []
    var imagesAndVideoAsset:[PHAsset] = []
    var images:[String] = []
    var videos:[String] = []
    var productDetails = NewSellProductDetails()
    var defaultData = NewSellDefaultData()
    var categoryVariantData:[VarientData]?
    var categorySubVariantData:[SubVarientData]?
    var weightData:[WeightData]?
    
    enum CodingKeys: String, CodingKey{
        case spu = "spu"
        case imagesAndVideo
        case images = "images"
        case videos = "videos"
        case productDetails = "productDetails"
        case defaultData = "defaultData"
        case categoryVariantData
        case categorySubVariantData
        case weightData
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(spu, forKey: .spu)
        try container.encode(imagesAndVideo, forKey: .imagesAndVideo)
        try container.encode(images, forKey: .images)
        try container.encode(videos, forKey: .videos)
        try container.encode(productDetails, forKey: .productDetails)
        try container.encode(defaultData, forKey: .defaultData)
        try container.encode(categoryVariantData, forKey: .categoryVariantData)
        try container.encode(categorySubVariantData, forKey: .categorySubVariantData)
        try container.encode(weightData, forKey: .weightData)
    }
}

public class NewSellProductDetails:Encodable {
    var title: String = ""
    var productDescription: String = ""
    var category:String = ""
    var categoryId:String = ""
    var condition: String = ""
    var unitType: String = ""
    var unitCount:Int = 0
    var weight:String = ""
    var weightTitle:String = ""
    var country:String = ""
    var countryTitle: String = ""
    var color: String = ""
    var varientTitle:String = ""
    var subVariantTitle:String = ""
    var varients = [NewSellProductVariants]()
    var autoBargain:Int = 0
    var maxBargainPercent:Int = 0
    var imageTags:[String] = []
    
    enum CodingKeys: String, CodingKey{
        case title = "title"
        case productDescription = "description"
        case category
        case categoryId = "categoryId"
        case condition = "condition"
        case unitType = "unitType"
        case unitCount = "unitCount"
        case weight = "weight"
        case country = "country"
        case color = "color"
        case varients = "varients"
        case autoBargain = "autoBargain"
        case maxBargainPercent = "maxBargainPercent"
        case imageTags
        case varientTitle
        case subVariantTitle
        case weightTitle
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(title, forKey: .title)
        try container.encode(productDescription, forKey: .productDescription)
        try container.encode(category, forKey: .category)
        try container.encode(categoryId, forKey: .categoryId)
        try container.encode(condition, forKey: .condition)
        try container.encode(unitType, forKey: .unitType)
        try container.encode(unitCount, forKey: .unitCount)
        try container.encode(weight, forKey: .weight)
        try container.encode(country, forKey: .country)
        try container.encode(color, forKey: .color)
        try container.encode(varients, forKey: .varients)
        try container.encode(autoBargain, forKey: .autoBargain)
        try container.encode(maxBargainPercent, forKey: .maxBargainPercent)
        try container.encode(imageTags, forKey: .imageTags)
        try container.encode(varientTitle, forKey: .varientTitle)
        try container.encode(subVariantTitle, forKey: .subVariantTitle)
        try container.encode(weightTitle, forKey: .weightTitle)
    }
    
}

public class NewSellProductVariants:Codable{
    var varient: String = ""
    var subvarient:String = ""
    var quantity: Int = 1
    var labelPrice:Int = 0
    var listedPrice:Int = 0
    var discount:String = ""
    var displayIcon:String = ""
    var variantImages:[String] = []
    var variantVideo:[String] = []
    var imagesAndVideo:[String] = []
    var imageAndVideoAsset:[PHAsset] = []
    var pickupCharges:Int = 0
    var commissionPercent:Int = 0
    
    enum CodingKeys: String, CodingKey{
        case varient = "varient"
        case subvarient = "subvarient"
        case quantity = "quantity"
        case labelPrice = "labelPrice"
        case listedPrice = "listedPrice"
        case displayIcon, discount
        case variantImages, variantVideo,imagesAndVideo
        case pickupCharges
        case commissionPercent
        
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(varient, forKey: .varient)
        try container.encode(subvarient, forKey: .subvarient)
        try container.encode(quantity, forKey: .quantity)
        try container.encode(labelPrice, forKey: .labelPrice)
        try container.encode(listedPrice, forKey: .listedPrice)
        try container.encode(discount, forKey: .discount)
        try container.encode(displayIcon, forKey: .displayIcon)
        try container.encode(variantImages, forKey: .variantImages)
        try container.encode(variantVideo, forKey: .variantVideo)
        try container.encode(imagesAndVideo, forKey: .imagesAndVideo)
        try container.encode(pickupCharges, forKey: .pickupCharges)
        try container.encode(commissionPercent, forKey: .commissionPercent)
    }
}

public class NewSellDefaultData:Encodable{
    var couponApplied: String = "NA"
    var address:Int = 0
    var pincode:String = ""
    var serviceType: String = ""
    var returnProduct :Int = 0
    var maxReturnDays:Int = 0
    var serviceName:String = ""
    var displayIcon:String = ""
    var commissionPercent:Int?
    var pickupCharges:Int?
    
    enum CodingKeys: String, CodingKey{
        case couponApplied = "couponApplied"
        case address = "addressId"
        case serviceType = "serviceType"
        case returnProduct = "return"
        case maxReturnDays = "maxReturnDays"
        case serviceName
        case displayIcon, pincode
        case commissionPercent, pickupCharges
        
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(couponApplied, forKey: .couponApplied)
        try container.encode(address, forKey: .address)
        try container.encode(serviceType, forKey: .serviceType)
        try container.encode(returnProduct, forKey: .returnProduct)
        try container.encode(maxReturnDays, forKey: .maxReturnDays)
        try container.encode(serviceName, forKey: .serviceName)
        try container.encode(displayIcon, forKey: .displayIcon)
        try container.encode(commissionPercent, forKey: .commissionPercent)
        try container.encode(pickupCharges, forKey: .pickupCharges)
        try container.encode(pincode, forKey: .pincode)
        
    }
}

array of class object:

var newSellListingSummaryProducts = [NewSellLocalDataModel]()

I want to update specific object's NewSellDefaultData value, but when change in specific object it will change in all object.

use Map method to update specific object value:

SingletonClass.shareInstance.newSellListingSummaryProducts = SingletonClass.shareInstance.newSellListingSummaryProducts.map{
            let mutableBook = $0
            if $0.currentCount == currentCount{
                mutableBook.data.defaultData = defaultData
            }
            return mutableBook
        }

use firstIndex method:

if let row = SingletonClass.shareInstance.newSellListingSummaryProducts.firstIndex(where: { $0.currentCount == currentCount }){
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.commissionPercent = self.commissionPercentage ?? 0
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.pickupCharges = self.pickUpCharges
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.displayIcon = self.serviceLogo ?? ""
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.serviceName = self.serviceName ?? ""
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.serviceType = self.serviceId ?? ""
                SingletonClass.shareInstance.newSellListingSummaryProducts[row].data.defaultData.couponApplied = couponId ?? ""
                
            }

Wwhich method I have to used for class object array to change NewSellDefaultData of specific index of object?