how to use?

[AceSha]

I just decided to use JsonDecoder to transform Json to model. I don't know how to handle the mismatch type. found this extension but don't know how to use.
Expecting response.

[DoubleHH]

Just define the propertys of model optional. For example:
struct User: Decodable {
var userId: Int?
}

And json:
let jsonString = {"userId":"1234"}

let decoder = JSONDecoder()
if let data = jsonString.data(using: String.Encoding.utf8) {
let user = try? decoder.decode(User.self, from: data)
}

So the key is to define the optional property