JSON data not copied to structure - swiftui

Question

This api is getting called correctly and is not falling into the "fetch failed" error line. The ContentView structure contains a standard menu with .onAppear at the bottom. Using the Xcode debugger I can see the data in decodedResponse but not in result. Is it really necessary to use #State results? Some of values in result / UserRates will be immediately pulled out and stored elsewhere. I would also like to use the retrieved date but currently my results definition keeps its non-defined. I'm assuming that to retrieve the data from the structure it is: UserRates.rates[9].key and UserRates.rates[9].value. Trying to read these with a print statement returns an error.
Galen Smith
struct UserRates: Codable {
let rates:[String: Double]
let base: String
let date: String
}
struct ContentView: View {
#State private var results = UserRates(rates: [:], base: "", date: "")
var body: some View {
... standard menu system in body
.onAppear(perform: loadCurrencies)
}
private func loadCurrencies() {
guard let url = URL(string: "https://api.exchangeratesapi.io/latest?base=USD") else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(UserRates.self, from: data) {
// we have good data – go back to the main thread
DispatchQueue.main.async {
// update our UI
**self.results = decodedResponse**
}
return
}
}
// problem if we fail into this
print("Fetch failed: \(error?.localizedDescription ?? "Unknown error")")
}.resume()
}
}

Answer 1

I had planned to copy 32 String / Double data pairs from decodedResponse to the UserRates structure then find and copy 11 exchange rates using the dictionary key / value method to a rateArray. But since the copy always fails, I decided to use the dictionary key / value method on the decodedResponse structure and copying directly to rateArray skipping the UserRate structure entirely. I may in the future use more exchange rates so that is why I load all available rates from my source. The real purpose of rateArray is to store the exchange rate reciprocals.
Galen