func decodingTypes() {
    let json = """
    [
    {
    "type": "Type1",
    "name": "Name 1"
    },
    {
    "type": "Type2",
    "value": 3
    }
    ]
    """

    enum Typing: String, Codable {
        case type1 = "Type1"
        case type2 = "Type2"
    }

    struct MetaClass: Codable {
        let type: Typing //You might not really need this var and make a custom CodingKeys for decoding it since it's in the `holder` value
        let holder: Holder

        init(from decoder: Decoder) throws {
            let container = try decoder.container(keyedBy: CodingKeys.self)
            self.type = try container.decode(Typing.self, forKey: .type)
            switch type {
            case .type1:
                self.holder = .named(try .init(from: decoder))
            case .type2:
                self.holder = .numered(try .init(from: decoder))
            }
        }
    }

    //Enum to manage multiple possible objects
    enum Holder: Codable {
        case named(Named)
        case numered(Numered)
    }

    struct Named: Codable {
        let type: Typing
        let name: String
    }

    struct Numered: Codable {
        let type: Typing
        let value: Int
    }

    do {
        let decoded = try JSONDecoder().decode([MetaClass].self, from: Data(json.utf8))
        print(decoded)
    } catch {
        print("Error while decoding: \(error)")
    }
}

decodingTypes()