A robust way to create JSON objects from JSONSerialization.

JSONHelpers.swift

//
//  Created by Vladimir Kelin on 2/8/19.
//  Copyright © 2019 Systematix Infotech. All rights reserved.
//

/*
 A more robust way to create JSON objects from JSONSerialization.
 Why more robust? See the explanation:
 http://kelindev.blogspot.com/2018/01/safer-parsing-with-jsonserialization-in.html
 */

import Foundation


extension String {
    init?(jsonObject: Any?) {
        guard jsonObject is NSNull == false else { return nil }
        
        let aNSObject = jsonObject as? NSObject
        if let description = aNSObject?.description {
            self = description
        } else {
            return nil
        }
    }
}

extension Int {
    init?(jsonObject: Any?) {
        if let number = jsonObject as? NSNumber {
            self = number.intValue
        } else if let string = jsonObject as? NSString {
            self = string.integerValue
        } else {
            return nil
        }
    }
}

extension Int16 {
    init?(jsonObject: Any?) {
        if let number = jsonObject as? NSNumber {
            self = number.int16Value
        } else if let string = jsonObject as? NSString {
            if let int16 = Int16(string as String) {
                self = int16
            } else {
                return nil
            }
        } else {
            return nil
        }
    }
}

extension Int32 {
    init?(jsonObject: Any?) {
        if let number = jsonObject as? NSNumber {
            self = number.int32Value
        } else if let string = jsonObject as? NSString {
            self = string.intValue
        } else {
            return nil
        }
    }
}

extension Bool {
    init?(jsonObject: Any?) {
        if let integer = Int(jsonObject: jsonObject) {
            self = integer != 0
        } else {
            return nil
        }
    }
}

extension Double {
    init?(jsonObject: Any?) {
        if let number = jsonObject as? NSNumber {
            self = number.doubleValue
        } else if let string = jsonObject as? NSString {
            self = string.doubleValue
        } else {
            return nil
        }
    }
}

extension Float {
    init?(jsonObject: Any?) {
        if let number = jsonObject as? NSNumber {
            self = number.floatValue
        } else if let string = jsonObject as? NSString {
            self = string.floatValue
        } else {
            return nil
        }
    }
}