Creating Custom JSON Mapper in Swift - ios

Question

Here performing two tasks :
1. Convert Dictionary to Model Object
2. Convert Model object to Dictionary
Wrote down following codes and its working perfectly :
JsonMapper.Swift
class JsonMapper
{
/**
*#Method : decodeUser
*#Param : Dictionary of type [String:Any]
*#ReturnType : User ( which is model )
*#Description: Responsible for mapping Dictionary to Model object
*/
func decodeUser(userDict:[String:Any]) -> User?
{
let decoder = JSONDecoder()
var objUser: User?
do {
let jsonData = try JSONSerialization.data(withJSONObject: userDict, options: JSONSerialization.WritingOptions.prettyPrinted)
objUser = try decoder.decode(User.self, from: jsonData)
print("✅ User Object: \n",objUser)
} catch {
print("❌ Error",error)
}
return objUser ?? User(id: "", type: “”,salary:””)
}
/**
*#Method : encodeUser
*#Param : User
*#ReturnType : Dictionary of type [String:Any]
*#Description: Responsible for mapping Model object User to Dictionary
*/
func encodeUser(modelObj:User) -> [String:Any]
{
let encoder = JSONEncoder()
var objProfileDict = [String:Any]()
do {
let data = try encoder.encode(modelObj)
objUserDict = (try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any])!
print("✅ json dictionary: \n",objProfileDict)
}
catch {
print("❌ Error \(error)")
}
return objUserDict
}
}
User Model :
struct User:Codable
{
let id : String
let type : String
let salary : String
}
Above code works perfectly fine, no problem.
Now the issue is :
1. Everytime i need to convert Dictionary into any model , here you can see Model User is fixed so i want to convert above code in generic model so that , i will pass any model and then it return me the result.
When i pass Dictionary it should return me the model which i will specify during run time , i want to make this generic for every model , so that Dictionary could be convert into any of specified model.
Kindly provide your valuable inputs.
**Note :
1.Dont want to use any 3rd party lib like ObjectMapper , etc.

Answer 1

The name JsonMapper is misleading here. What you really mean is a dictionary mapper. Your approach is fine. If you want it to be generic, just pass the type. I'd probably do it this way:
extension JSONDecoder {
/**
*#Method : decodeUser
*#Param : Dictionary of type [String:Any]
*#ReturnType : User ( which is model )
*#Description: Responsible for mapping Dictionary to Model object
*/
func decode<T: Decodable>(_ type: T.Type, from dictionary: [String: Any]) throws -> T
{
let jsonData = try JSONSerialization.data(withJSONObject: dictionary)
return try decode(T.self, from: jsonData)
}
}
And similarly for JSONEncoder.