nyan.js

(function(global){
  Nyan = function(a, b){
    this.a = a;
    this.b = b;
  };

  Nyan.prototype.klass = 'Nyan'; // ここがクソださい
  Nyan.prototype.nyan = function(){return this.a + this.b};
  global.Nyan = Nyan; // export

  var serializer = {
    serialize: function(obj){
      if (obj.klass === undefined) {
        throw new Error("object to be serialized must have 'klass' attribute")
      }
      return JSON.stringify({
        klass: obj.klass,
        obj: obj,
      });
    },

    deserialize: function(string){
      json = JSON.parse(string);
      obj = json.obj;
      klass = json.klass;
      obj.prototype = global[klass].prototype;
      return obj;
    }
  };

  var nyan = new Nyan('a', 'b');
  var serializedNyan = serializer.serialize(nyan);
  console.log(serializer.serialize(nyan));// => {"klass":"Nyan","obj":{"a":"a","b":"b"}}

  var nyanClone = serializer.deserialize(serializedNyan);

  console.log(nyan.a); // => "a"
  console.log(nyan.b); // => "b"
  console.log(nyan.nyan()); // => "ab"

})(this);