Hi guys,for the same URL request I can have a different json response from the API. For success I've something like this:

{
    "error": "false",
    "value": {
        "person": {
            "personId": 1529853,
            "name": "test",
            "firstName": "tezt",
            "civility": "MR",
            "fidelityCode": "LM57CC",
            "phoneCode": "+237",
            "phoneNumber": "+237",
            "cniCode": null,
            "email": "test6@adwa.cm",
            "vipStatus": 0,
            "activationStatus": 1,
            "countryCode": 30,
            "birthDate": "2002-10-12",
            "searchStatus": "RAS"
        }
    }
}

For error I've something like this:

{
    "error": "false",
    "value": {
        "person": -1
    }
}

How can I handle it to know when it's a success or error?

Basically, you need to use an enum for the "person" key with two cases have associated values of either an Int or a Person. Here is a SwiftUI view that I whipped up to demonstrate:

import SwiftUI

struct Person: Decodable {
    let personId: Int
    let name: String
    let firstName: String
    let civility: String
    let fidelityCode: String
    let phoneCode: String
    let phoneNumber: String
    let cniCode: String?
    let email: String
    let vipStatus: Int
    let activationStatus: Int
    let countryCode: Int
    let birthDate: String
    let searchStatus: String
}

enum PersonOrError: Decodable {
    case personVal(Person)
    case errorVal(Int)

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if let intVal = try? container.decode(Int.self) {
            self = .errorVal(intVal)
            return
        }
        if let personVal = try? container.decode(Person.self) {
            self = .personVal(personVal)
            return
        }
        throw DecodingError.typeMismatch(PersonOrError.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for ValueUnion"))
    }
}

struct Value: Decodable {
    let person: PersonOrError
}

struct PEResponse: Decodable {
    let error: String
    let value: Value
}

struct PersonOrErrorView: View {

    let jsonError = {
        return """
{
    "error": "false",
    "value": {
        "person": -1
    }
}
""".data(using: .utf8)!
    }()

    let jsonPerson = {
      return """
{
    "error": "false",
    "value": {
        "person": {
            "personId": 1529853,
            "name": "test",
            "firstName": "tezt",
            "civility": "MR",
            "fidelityCode": "LM57CC",
            "phoneCode": "+237",
            "phoneNumber": "+237",
            "cniCode": null,
            "email": "test6@adwa.cm",
            "vipStatus": 0,
            "activationStatus": 1,
            "countryCode": 30,
            "birthDate": "2002-10-12",
            "searchStatus": "RAS"
        }
    }
}
""".data(using: .utf8)!
    }()

    enum PorE {
        case person, error
    }
    @State private var whichJSON: PorE = .person

    @State private var textDisplay: String = ""

    var body: some View {
        VStack {
            Text(textDisplay)
            Button("Switch") {
                whichJSON = whichJSON == .person ? .error : .person
            }
        }
        .onAppear { loadJSON() }
        .onChange(of: whichJSON) { _ in
            loadJSON()
        }
    }

    func loadJSON() {
        let decoder = JSONDecoder()
        do {
            let response =
                try decoder.decode(PEResponse.self,
                                   from: whichJSON == .person ? jsonPerson : jsonError)
            switch response.value.person {
            case .errorVal(let i): textDisplay = "Error \(i)"
            case .personVal(let p): textDisplay = p.name
            }
        }
        catch {
            textDisplay = "Error!"
        }
    }
}

struct PersonOrErrorView_Previews: PreviewProvider {
    static var previews: some View {
        PersonOrErrorView()
    }
}

Hopefully this makes sense.

I totally forgot after testing, thank you so much 🙏