Node.js and exported variables

Question

I\'m trying to use one script for the communal storage of \"global\" variables, and other scripts can require that script to see those variables, but that appears to not be

Answer 1

Do not attempt to use globals in node.js. Also note that require will reference a cached object and will not actually re-require the same file more than once.

Here's a pretty generic example of how you might start setting up a card game without using global variables

lib/deck.js

var SUITS = ["H", "C", "D", "S"],
    RANKS = ["A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K"];

var Deck = module.exports = function Deck() {
  this.cards = [1, 2, 3, ..., 52];
  this.shuffle();
};

Deck.prototype.shuffle = function shuffle() {
  // shuffle this.cards
};


Deck.prototype.dealCard = function dealCard() {
  var id = this.cards.shift();
  return {id: id, rank: RANKS[id%13], suit: SUITS[id%4]};
};

lib/game.js

var Deck = require("./deck");

var Game = module.exports = function Game(numCards) {
  this.numCards = numCards;
  this.deck = new Deck();
};

Game.prototype.dealCards = function dealCards(player) {
  for (var i=0; i

lib/player.js

var EventEmitter = require("events").EventEmitter;

var Player = module.exports = function Player(name) {
  this.name = name;
  this.cards = [];
};

Player.prototype = Object.create(EventEmitter.prototype, {constructor: {value: Player}};

// ...

lib/session.js

var EventEmitter  = require("events").EventEmitter,
    Game          = require("./game"),
    Player        = require("./player");

var Session = module.exports = function Session(numCards) {
  EventEmitter.call(this);
  this.game = new Game(numCards);
  this.players = [];
  this.scores = [];
};

Session.prototype = Object.create(EventEmitter.prototype, {constructor: {value: Session}});

Session.prototype.addPlayer = function addPlayer(player) {
  // add the player
  this.players.push(player);

  // deal the player some cards
  this.game.dealCards(player);

  // setup event listeners
  player.on("score", function(points) {
    this.addScore(player, points);
  });

  player.on("playerTurn", function(event) {
    // ...
  });
};

Session.prototype.addScore = function(player, points) {
  if (this.scores[player.id] === undefined) {
    this.scores[player.id] = 0;
  }
  this.scores[player.id] += points;
};

run.js

var Session  = require("./session"),
    numCards = 2;

var sessionInstance = new Session(numCards);

sessionInstance.on("addPlayer", function(player) {
  this.addPlayer(player);
});

// e.g.,
// setup a net.Server and fire "addPlayer" when a user connects