可以写个native.js调用ios原生NSString方法的例子吗

可以写个调用ios原生NSString方法的示例吗，下面是我写的代码，但是什么都不显示

var data = "%7B%22isSuccess%22%3A%22true%22%2C%22response%22%3A%7B%22message%22%3A%22success%22%2C%22code%22%3A%22M-Y000000%22%2C%22noticelist%22%3A%5B%5D%7D%2C%22sign%22%3A%22ad194b11807572131963140e16724ca6%22%7D";

var NSString = plus.ios.importClass("NSString");
var dataStr = new NSString(data);

console.log(dataStr.stringByReplacingPercentEscapesUsingEncoding("UTF-8"));

打印内容为空，请问哪有问题？