Wrapping NSJSONSerialization to make the methods simpler/easy to use.

NSJSONSerialization-wrapper.swift

//: Playground - noun: a place where people can play

import Foundation

public class JSON {
    public static func toNSData(obj: AnyObject) -> NSData? {
        return try? NSJSONSerialization.dataWithJSONObject(obj, options: NSJSONWritingOptions(rawValue: 0))
    }

    public static func toJSONObj(obj: NSData) -> AnyObject? {
        return try? NSJSONSerialization.JSONObjectWithData(obj, options: NSJSONReadingOptions(rawValue: 0))
    }

    private static func fromJSONObj(type: AnyObject) -> AnyObject? {
        if let type = type as? NSData, tempJSON = toJSONObj(type) {
            return tempJSON
        } else if let type = type as? String, data = type.dataUsingEncoding(NSUTF8StringEncoding) {
            return fromJSONObj(data)
        }
        return nil
    }

    public static func toJSONDict(type: AnyObject) -> [String:AnyObject]? {
        return fromJSONObj(type) as? [String:AnyObject]
    }

    public static func toJSONArray(type: AnyObject) -> [AnyObject]? {
        return fromJSONObj(type) as? [AnyObject]
    }

    public static func toJSONString(type: AnyObject) -> String? {
        if let type = type as? String {
            return type
        } else if let type = type as? [String:AnyObject],
            anyJSON = toNSData(type) {
                return String(data: anyJSON, encoding: NSUTF8StringEncoding)
        } else if let type = type as? [AnyObject],
            anyJSON =  toNSData(type) {
                return String(data: anyJSON, encoding: NSUTF8StringEncoding)
        } else if let type = type as? NSData {
            return String(data: type, encoding: NSUTF8StringEncoding)
        }
        return nil
    }
}

// usage
let dict = ["boo":"foo", "moo":"lo"]
let str = JSON.toJSONString(dict)
let data = JSON.toJSONDict(str!)