Convert string to Date/Int/Double using codable - json

Question

I am getting a response from an API but the problem is that the API is sending values back as a string of dates and doubles. I am therefore getting the error "Expected to decode Double but found a string/data instead." I have structured my struct like this to solve the problem but this seems like a patch. Is there any better way to fix this issue? I feel like apple has thought of this and included something natively to address this.
struct SimpleOrder:Codable{
var createdDate:Date! {
return createdDateString.dateFromISO8601
}
var createdDateString:String
var orderId:String!
var priceVal:Double!
var priceString:String{
didSet {
priceVal = Double(self.priceString)!
}
}
private enum CodingKeys: String, CodingKey {
//case createdDate
case createdDateString = "time"
case orderId = "id"
case priceVal
case priceString = "price"
}
}
I don't know if this is relevant but this is how it is being used. I am getting the data as a string and converting it to data which is stored in the dataFromString variable
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601 //This is irrelevant though because the date is returned as a string.
do{
let beer = try decoder.decode(SimpleOrder.self, from: dataFromString)
print ("beer is \(beer)")
}catch let error{
print ("error is \(error)")
}
As a result of using codable, I am getting an error when trying to get an empty instance of SimpleOrder. Before I was using codable, I had no issues using SimpleOrder() without any arguments.
Error: Cannot invoke initializer for type 'SimpleOrder' with no arguments
var singlePoint = SimpleOrder()

Answer 1

struct SimpleOrder: Codable {
var created: Date?
var orderId: String?
var price: String?
private enum CodingKeys: String, CodingKey {
case created = "time", orderId = "id", price
}
init(created: Date? = nil, orderId: String? = nil, price: String? = nil) {
self.created = created
self.orderId = orderId
self.price = price
}
}
extension SimpleOrder {
var priceValue: Double? {
guard let price = price else { return nil }
return Double(price)
}
}
extension Formatter {
static let iso8601: DateFormatter = {
let formatter = DateFormatter()
formatter.calendar = Calendar(identifier: .iso8601)
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.timeZone = TimeZone(secondsFromGMT: 0)
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSXXXXX"
return formatter
}()
}
Decoding the json data returned by the API:
let jsonData = Data("""
{
"time": "2017-12-01T20:41:48.700Z",
"id": "0001",
"price": "9.99"
}
""".utf8)
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(Formatter.iso8601)
do {
let simpleOrder = try decoder.decode(SimpleOrder.self, from: jsonData)
print(simpleOrder)
} catch {
print(error)
}
Or initialising a new object with no values:
var order = SimpleOrder()