Values of Array of struct are nil - ios

Question

I am pretty new to Swift and as an exercise I try to create an App with Swift 5, which should show you the Weather at a Location you searched for.
Right now I am trying to implement a function that can turn a local JSON file in a struct I am using.
The JSON file is located at the same directory as all the other files.
The JSON for testing purposes looks like this:
[
{
"id": 833,
"name": "Ḩeşār-e Sefīd",
"state": "",
"country": "IR",
"coord": {
"lon": 47.159401,
"lat": 34.330502
}
},
{
"id": 2960,
"name": "‘Ayn Ḩalāqīm",
"state": "",
"country": "SY",
"coord": {
"lon": 36.321911,
"lat": 34.940079
}
}
]
The struct:
struct Root: Codable {
let jsonWeather: [JsonWeather]?
}
struct JsonWeather: Codable {
let id: Int
let name: String
let state: String
let country: String
let coord: Coord
enum CodingKeys: String, CodingKey {
case id = "id"
case name = "name"
case state = "state"
case country = "country"
case coord = "coord"
}
}
The function that i am working on:
func loadJson(fileName: String) -> Void{
if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
do {
let data = try Data(contentsOf: url)
let jsonData = try JSONDecoder().decode(Array<Root>.self, from: data)
print(type(of: jsonData)) // Array<Root>
print(jsonData) // [WeatherApp.Root(jsonWeather: nil), WeatherApp.Root(jsonWeather: nil)]
} catch {
print("error:\(error)")
}
}
}
After all I wanted to see how the result looks like and I noticed that each jsonWeather in Root is nil
So in the end I understand that the values are nil because I allow them to be nil by setting an optional in the Root struct, but I dont quite understand why they are turning nil because there is data given. Also I don't know how I would implement it without being an optional.
This is my first time using JSONDecoder and Optionals in Swift.
Could anyone point out what I did wrong (or understood wrong) and how to fix this issue

Answer 1

Since your JSON is just of array of objects, you don't need a top-level struct like Root.
Get rid of your Root struct, and just decode an array of JsonWeathers:
let jsonData = try JSONDecoder().decode([JsonWeather].self, from: data)
(Note that there is no difference between [JsonWeather].self and Array<JsonWeather>.self - I just chose to do it this way since it's shorter.)