Deserialize json string UTF8 encoding

jsondecode.swift

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

import UIKit

let jsonString = "{\"username\" : \"thunderbird\",  \"password\" : \"tb00110\"}"

func jsonDecodeString(json: String) -> Dictionary<String, AnyObject>? {
    let json:NSData = jsonString.dataUsingEncoding(NSUTF8StringEncoding)!
    do {
        return try NSJSONSerialization.JSONObjectWithData(json, options: NSJSONReadingOptions.MutableContainers) as? Dictionary<String, AnyObject>
    } catch {
        print("error")
    }
    return nil
}

jsonDecodeString(jsonString)