Initialization and Storage Error of API Data - swiftui

Question

I have an exchange rate API initialization / storage problem. I read in some currency exchange rates and would like to store the data temporally in moneyRates then move the data to rateArray as ordered data. I am getting the error "No exact matches in call to initializer". The error is occurring at the line that begins "let result = try JSONSerialization...". I am also seeing a message in the sidebar (Xcode gray !) "/Foundation.Data:29:23: Candidate requires that the types 'MoneyRates' and 'UInt8' be equivalent (requirement specified as 'S.Element' == 'UInt8')". I'm guessing that I need to initialize moneyRates with some kind of format info.
I would like some explanation of the moneyRates error and how to resolve it. I'm not concerned with rateArray at this point. Thanks for your assistance.
struct MoneyRates {
let date: String
let base: String
let rates: [String: Double]
}
class CurrencyRates: ObservableObject{
#Published var moneyRates: [MoneyRates]
#Published var rateArray = [Double] ()
init() {
if UserDefaults.standard.array(forKey: "rates") != nil {
rateArray = UserDefaults.standard.array(forKey: "rates") as! [Double]
} else {
rateArray = [Double] (repeating: 0.0, count: 170)
UserDefaults.standard.set(self.rateArray, forKey: "rates")
}
}
// retrieve exchange rates for all 150+ countries from internet and save to rateArray
func updateRates(baseCur: String) {
let baseUrl = "https://cdn.jsdelivr.net/gh/fawazahmed0/currency-api#1/latest/currencies/"
let requestType = ".json"
guard let url = URL(string: baseUrl + baseCur + requestType) else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
do {
let result = try JSONSerialization.jsonObject(with: Data(moneyRates)) as! [String:Any] // <-- error is occurring here
var keys = Array(arrayLiteral: result.keys)
if let dateIndex = keys.firstIndex(of: "date"),
let date = result[keys[dateIndex]] as? String, keys.count == 2 {
keys.remove(at: dateIndex)
let base = keys.first!
let rates = MoneyRates(date: date, base: base, rates: result[base] as! [String:Double])
print(rates)
}
} catch {
print(error)
}
}
}.resume()
}
}

Answer 1

If you're trying to decode the result that you get from the URLSession, then instead of passing Data(moneyRates) to decode, you should be passing data from the dataTask closure:
let result = try JSONSerialization.jsonObject(with: data) as! [String:Any]