SeparateMapping

SeparateMapping.swift

struct User {
  let id: Int
  let name: String
}

class UserMapper {
  func map(_ dictionary: [String: Any]) -> User? {
    guard let id = dictionary["id"] as? Int else { return nil }
    guard let name = dictionary["user_name"] as? String else { return nil }
    
    return User(id: id, name: name)
  }
}

let bobUser = UserMapper().map(userDictionary)