javascript - Prototype methods not seen in NodeJS session -

i'm trying learn javascript , nodejs building small game, , i'm running problem. when attach object session, whenever reaccess session no longer have access prototype methods define on it.

in 1 file called 24.js, have

function deck() {     this.cards = [];     (var = 0; < 52; i++) {         this.cards[i] = math.floor(i / 4) + 1;     }     this.done = false; }  function gamestate() {     // holds game state , game logic     this.time = 0;     this.score = 0;     this.deck = new deck();     this.deck.deal(); } deck.prototype.deal = function() {     // not important }  var gamemaker = exports = module.exports = function() {     return new gamestate(); } 

then in main file have

var express = require('express'); var gamemaker = require('./24.js');  var app = express(); app.use(express.static(__dirname + '/static')); app.use(express.urlencoded()); app.use(express.cookieparser()); app.use(express.session({     secret: 'supersecret',     key: 'express.sid' }));  app.get('/', function (req, res) {     if (!req.session.game) {         req.session.game = gamemaker();     }     var game = req.session.game;     // access data game send client });  app.post('/verify', function (req, res) {     // assumes game exists, check later     var game = req.session.game;     game.score += 1;     game.deck.deal();     res.redirect("/"); }); 

i error whenever post, because says object #<object> has no method 'deal'. checked , can still call deal() method first time load page, , can access other information (like score of game, or cards last dealt.) thing breaks method calls on same session.

the problem when sessions saved between requests, serialized json.stringify(req.session). means objects converted plain js objects , object no longer have prototype set deck.prototype when parsed json.

you should not storing complex data structures in session. instead have own logic get/set session values needed recreate deck.