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I am trying to parse a response using the JSONDecoder . If there is value for the corresponding key then it goes well, but if there is null value for a key then it fails to compile with the following error.

valueNotFound(Swift.String, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "Results", intValue: nil), _JSONKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "VehicleName", intValue: nil)], debugDescription: "Expected String value but found null instead.", underlyingError: nil))

guard let obj = try? JSONDecoder().decode(ShipmentsResponse.self, from: json) else {return}
here is the Shipment class that i defied
class ShipmentResponse : Codable {
    var ItemId: String = ""
    var VehicleName: String  = ""
    var VehicleNumber: String  = ""
    convenience required init(from decoder: Decoder) throws
        self.init()
        let values = try decoder.container(keyedBy: CodingKeys.self)
        ItemId = try values.decode(String.self, forKey: .ItemId)
            _ = try values.decode(String.self, forKey: .VehicleName)
        } catch {
            print(error)
        VehicleName = try values.decode(String.self, forKey: .VehicleName)
        VehicleNumber = try values.decode(String.self, forKey: .VehicleNumber)
Here is the json
    "ItemId": "8af66c87-9099-42a7-8a34-39def02160ac",
    "VehicleName": null,
    "VehicleNumber": null
Expected value is string but we are getting null in the response. So the decoder throws an error if it's going to decode a null value to a non-optional type. So, handle it by making the empty string in the parameters.
Model code:
class ShipmentResponse : Codable {
    var itemId: String
    var vehicleName: String
    var vehicleNumber: String
    enum CodingKeys: String, CodingKey {
        case itemId = "ItemId"
        case vehicleName = "VehicleName"
        case vehicleNumber = "VehicleNumber"
    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.itemId = try container.decodeIfPresent(String.self, forKey: .itemId) ?? ""
        self.vehicleName = try container.decodeIfPresent(String.self, forKey: .vehicleName) ?? ""
        self.vehicleNumber = try container.decodeIfPresent(String.self, forKey: .vehicleNumber) ?? ""
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(itemId, forKey: .itemId)
        try container.encode(vehicleName, forKey: .vehicleName)
        try container.encode(vehicleNumber, forKey: .vehicleNumber)
JSON parsing:
let data = """
    "ItemId": "8af66c87-9099-42a7-8a34-39def02160ac",
    "VehicleName": null,
    "VehicleNumber": null
""".data(using: String.Encoding.utf8)!
    let jsonData = try JSONDecoder().decode(ShipmentResponse.self, from: data)
    print("\(jsonData.itemId) \(jsonData.vehicleNumber)")
} catch let error {
    print(error)
        
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