Deserialization JSON swift 4.2 - json

Question

I try to deserialize my JSON by using Decodable protocol, also i use enum with CodingKey, but it doesn't work. I need only nested array (start with "indicator"), and only few fields (all of them in struct). I tried a lot of different options, but unfortunately..
P.S. Also i tried to do it without CodingKey. Anyway response was: "Swift.DecodingError.keyNotFound(CodingKeys(stringValue: "country", intValue: nil)" Ofc i read this, maybe array is a reason(i mean this strange intValue)?
JSON
[
{
"page":1,
"pages":2,
"per_page":50,
"total":59,
"sourceid":"2",
"lastupdated":"2019-03-21"
},
[
{
"indicator":{
"id":"IP.PAT.RESD",
"value":"Patent applications, residents"
},
"country":{
"id":"SS",
"value":"South Sudan"
},
"countryiso3code":"SSD",
"date":"2018",
"value":null,
"unit":"",
"obs_status":"",
"decimal":0
},
{
"indicator":{
"id":"IP.PAT.RESD",
"value":"Patent applications, residents"
},
"country":{
"id":"SS",
"value":"South Sudan"
},
"countryiso3code":"SSD",
"date":"2017",
"value":null,
"unit":"",
"obs_status":"",
"decimal":0
},
...
]
]
My code
struct CountryObject: Decodable{
var country: CountryInfo
var date: Int
var value: Int?
private enum RawValues: String, Decodable{
case date = "date"
case vallue = "value"
}
}
struct CountryInfo: Decodable{//Country names
var id: String?
var value: String?
private enum RawValues: String, Decodable{
case id = "id"
case value = "value"
}
}//
let urlString = "https://api.worldbank.org/v2/country/SS/indicator/IP.PAT.RESD?format=json"
guard let url = URL(string: urlString) else {return}
URLSession.shared.dataTask(with: url) {(data,response,error) in
guard let data = data else {return}
guard error == nil else {return}
do{
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let countryObject = try! decoder.decode([CountryObject].self, from: data)
print(countryObject)
}catch let error{
print(error)
}
}.resume()

Answer 1

Create a root struct and decode the array with unkeyedContainer
struct Root : Decodable {
let info : Info
let countryObjects : [CountryObject]
init(from decoder: Decoder) throws {
var arrayContrainer = try decoder.unkeyedContainer()
info = try arrayContrainer.decode(Info.self)
countryObject = try arrayContrainer.decode([CountryObject].self)
}
}
struct Info : Decodable {
let page, pages, perPage: Int
let lastupdated: String
}
struct CountryObject : Decodable {
let country: CountryInfo
let date: String
let value: Int?
}
struct CountryInfo : Decodable { //Country names
let id: String
let value: String
}
...
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
do {
let root = try decoder.decode(Root.self, from: data)
let countryObjects = root.countryObjects
print(countryObjects)
} catch { print(error) }
(De)serializing the JSON twice is unnecessarily expensive.