Swift: Decode flat JSON to an structured object

Question

wonder if there is a simple way to get a simple flat json to a struct with a structure

json:

 {
        "date": "2022-02-24T00:00:00.000Z",
        "personel": 800,
        "plane": 7,
        "drone": 6,
    }

what I want is to get a structure like this:

struct Day: Codable, Identifiable {
    var id = UUID()
    var date : String
    var dayData: [DayData]

    struct DayData: Codable {
    var personel: Int
    var plane: Int
    var drone: Int
   }
}

I thought there should be some simple way to make it work

Answer 1

As specified in comments it would be better to create temporary DBObject and initialize your Day object with it.

Simple DBObject:

struct DBObject: Decodable {
    let date: String?
    let personel, plane, drone: Int?
}

Adding init() to your Day

struct Day: Codable, Identifiable {
    var id = UUID()
    var date : String
    var dayData: [DayData]
    
    init(from dbObject: DBObject) {
        let dayData = DayData(personel: dbObject.personel ?? 0,
                              plane: dbObject.plane ?? 0,
                              drone: dbObject.drone ?? 0)
        self.dayData = [dayData]
        self.date = dbObject.date ?? ""
    }
    
    struct DayData: Codable {
        var personel: Int
        var plane: Int
        var drone: Int
    }
}

Decoding Day from Data response:

func returnDay(from dataResponse: Data) -> Day {
    do {
        let decoder = JSONDecoder()
        let dbObject = try decoder.decode(DBObject.self,
                                          from: dataResponse)
        return Day(from: dbObject)
    } catch {
        fatalError("Cannot decode object")
    }
}