Modeling JSON Currency Object - swiftui

Question

I have a question concerning modeling JSON data.
I am trying to figure out how to decode JSON exchange rate data. The JSON file consists of a date, base currency ("eur" in the example below), and some currencies with rates compared to the base currency. It would be a straight forward nested JSON object without the base currency, but with the base currency thrown in the middle without a key I'm not sure where to begin.
Do I need codingKeys for the base currency and rates? How do you handle the missing base currency key?
extension MoneyRates: Decodable {
enum CodingKeys: String, CodingKey {
case base = ??
case rates = ??
}
}
Here is some Xcode Playground sample code:
let json =
"""
{
"date": "2021-03-12",
"eur": {
"aed": 4.420217,
"afn": 93.3213,
"all": 123.104693,
"amd": 628.026474,
}
}
""".data(using: .utf8)
class MoneyRates: Decodable {
let date: String
let base: String
var rates: [String: Double] = [:]
}

Answer 1

Honestly for this particular JSON I'd use traditional JSONSerialization
struct MoneyRates {
let date: String
let base: String
let rates: [String: Double]
}
let json =
"""
{
"date": "2021-03-12",
"eur": {
"aed": 4.420217,
"afn": 93.3213,
"all": 123.104693,
"amd": 628.026474,
}
}
"""
do {
let result = try JSONSerialization.jsonObject(with: Data(json.utf8)) as! [String:Any]
var keys = Array(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)
}