ValueWrapper.swift

//
//  ValueWrapper.swift
//  ADKATech.com
//
//  Created by Amr Elghadban on 9/20/18.
//  Copyright © 2018 Mobile DevOps. All rights reserved.
//

import Foundation

enum ValueWrapper: Codable {
    case stringValue(String)
    case intValue(Int)
    case doubleValue(Double)
    case boolValue(Bool)

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if let value = try? container.decode(String.self) {
            self = .stringValue(value)
            return
        }
        if let value = try? container.decode(Bool.self) {
            self = .boolValue(value)
            return
        }
        if let value = try? container.decode(Double.self) {
            self = .doubleValue(value)
            return
        }
        if let value = try? container.decode(Int.self) {
            self = .intValue(value)
            return
        }

        throw DecodingError.typeMismatch(ValueWrapper.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for ValueWrapper"))
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        switch self {
        case let .stringValue(value):
            try container.encode(value)
        case let .boolValue(value):
            try container.encode(value)
        case let .intValue(value):
            try container.encode(value)
        case let .doubleValue(value):
            try container.encode(value)
        }
    }

    var rawValue: String {
        var result: String
        switch self {
        case let .stringValue(value):
            result = value
        case let .boolValue(value):
            result = String(value)
        case let .intValue(value):
            result = String(value)
        case let .doubleValue(value):
            result = String(value)
        }
        return result
    }

    var intValue: Int? {
        var result: Int?
        switch self {
        case let .stringValue(value):
            result = Int(value)
        case let .intValue(value):
            result = value
        case let .boolValue(value):
            result = value ? 1 : 0
        case let .doubleValue(value):
            result = Int(value)
        }
        return result
    }

    var boolValue: Bool? {
        var result: Bool?
        switch self {
        case let .stringValue(value):
            result = Bool(value)
        case let .boolValue(value):
            result = value
        case let .intValue(value):
            result = Bool(truncating: value as NSNumber)
        case let .doubleValue(value):
            result = Bool(truncating: value as NSNumber)
        }
        return result
    }
}

How to use this wrapper, can we give example code to encode and decode JSON data.

How to use this wrapper, can we give example code to encode and decode JSON data.

Use this enum as type for your variable
Assume you have an employee and you wanna identify his salary

struct Employee: Codable {
let name: String?
let salary: ValueWrapper?
}

This is awesome! Thanks @amrangry, very nicely written.
Just wondering if we should try and decode the Int before the Double? If we are decoding, say, 2 then we'd prefer an Int with value 2 instead of a Double of 2.0?

@BenShutt
It good question, actually the usage of parsed value will vary according to your code needs,
let back again to the main pain that leads me to such a solution is actually that sometimes the response from API come as String or Int for the same parameter
for example :
[ { "name": "Amr", "age": "29" }, { "name": "Ben", "age": 28 } ]
the problem now how you would parse this, my solution is to decode using this helper type
then the usage depends on your business logic

thank you so much, you safe my life ^^

thank you so much, you safe my life ^^

You are most welcome @hhg21011998, glad that it helps