Decoding an array of objects with nested heterogeneous child objects

Viewed 230

An example of the response from the server is below.

The list consists of elements that have heterogeneous substructures in the info fields. Each of them contains 3 fields with the same types, but they have different keys.

I don't know how to decode this, I haven't encountered such a problem so far. I can't find an example on the Internet that fits this case.

I wanted to decode the enum type at the beginning and select the appropriate info structure based on it, but it doesn't work.

I would very much appreciate your help.

{
  "data":[
    {
      "type":"league",
      "info":{
        "name":"NBA",
        "sport":"Basketball",
        "website":"https://nba.com/"
      }
    },
    {
      "type":"player",
      "info":{
        "name":"Kawhi Leonard",
        "position":"Small Forward",
        "picture":"https://i.ibb.co/b5sGk6L/40a233a203be2a30e6d50501a73d3a0a8ccc131fv2-128.jpg"
      }
    },
    {
      "type":"team",
      "info":{
        "name":"Los Angeles Clippers",
        "state":"California",
        "logo":"https://logos-download.com/wp-content/uploads/2016/04/LA_Clippers_logo_logotype_emblem.png"
      }
    }
  ]
}
1 Answers

Your code on pastebin is too complicated, I mean this

let jsonString = """
{
  "data":[
    {
      "type":"league",
      "info":{
        "name":"NBA",
        "sport":"Basketball",
        "website":"https://nba.com/"
      }
    },
    {
      "type":"player",
      "info":{
        "name":"Kawhi Leonard",
        "position":"Small Forward",
        "picture":"https://i.ibb.co/b5sGk6L/40a233a203be2a30e6d50501a73d3a0a8ccc131fv2-128.jpg"
      }
    },
    {
      "type":"team",
      "info":{
        "name":"Los Angeles Clippers",
        "state":"California",
        "logo":"https://logos-download.com/wp-content/uploads/2016/04/LA_Clippers_logo_logotype_emblem.png"
      }
    }
  ]
}
"""

struct Response: Decodable {
    let data: [Datum]
}

struct League: Codable {
    let name: String
    let sport: String
    let website: URL
}

struct Player: Codable {
    let name: String
    let position: String
    let picture: URL
}

struct Team: Codable {
    let name: String
    let state: String
    let logo: URL
}

enum Datum: Decodable {
    case league(League)
    case player(Player)
    case team(Team)
    
    enum DatumType: String, Decodable {
        case league
        case player
        case team
    }
    
    private enum CodingKeys : String, CodingKey { case type, info }
 
    init(from decoder : Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        let type = try container.decode(DatumType.self, forKey: .type)
        switch type {
        case .league:
            let item = try container.decode(League.self, forKey: .info)
            self = .league(item)
        case .player:
            let item = try container.decode(Player.self, forKey: .info)
            self = .player(item)
        case .team:
            let item = try container.decode(Team.self, forKey: .info)
            self = .team(item)
        }
    }
}

do {
    let response = try JSONDecoder().decode(Response.self, from: Data(jsonString.utf8))
    let data = response.data
    print(data)
//    receivedData.forEach { (datum) in
//        let cell = Cell()
//        cell.configure(with: datum.info.rowData)
//        cells.append(cell)
//    }
//    cells.forEach({ print($0.title, $0.subtitle) })
} catch {
    print(error)
}

In the cell switch on the type

switch datum {
    case .league(let league): // so something with league
    case .player(let player): // so something with player
    case .team(let team): // so something with team
} 
Related