leaderboard.js

// Set up a collection to contain player information. On the server,
// it is backed by a MongoDB collection named "players".

Players = new Meteor.Collection("players"); // Lado del servidor: crea una coleccion llamado "players"
                                            // tambien se apunta que cliente le esta llamando

// Codigo reactivo(ejecuta el codigo cuando hay un cambio en la sesion)
if (Meteor.isClient) {
  Template.leaderboard.players = function () { // se reejecuta la siguiente linea cuando hay un cambio de sesion
    return Players.find({}, {sort: {score: -1, name: 1}}); // se ejecuta esto
  };

  Template.leaderboard.selected_name = function () {
    var player = Players.findOne(Session.get("selected_player"));
    return player && player.name;
  };

  Template.player.selected = function () {
    return Session.equals("selected_player", this._id) ? "selected" : ''; // fondo en amarillo el que esta seleccionado
  };

  Template.leaderboard.ordenar = function () {
    var order = "Nombre";
    if (Session.get("order")) {
      order = "Punto";
    }
    return order;
  };

  Template.leaderboard.events({
    'click input.inc': function () {
      Players.update(Session.get("selected_player"), {$inc: {score: 5}});
    },

    'click #sort': function () {
        Session.set("order", !Session.get("order"));
    }
  });

  Template.player.events({
    'click': function () { // hace que cambie la sesion al darle un click
      Session.set("selected_player", this._id);
    }
  });

  Template.leaderboard.players = function() {
    var order = Session.get("order") ? {name: 1, score: -1} : {score: -1, name: 1};
    return Players.find({}, {sort: order});
  };

  Template.addPlayer.events({
    'click input.add': function () {
      if (playerName.value != '')
        Players.insert({name: playerName.value, score: 0});
    }
  });

}

// On server startup, create some players if the database is empty.
if (Meteor.isServer) {
  Meteor.startup(function () {
    if (Players.find().count() === 0) {
      var names = ["Ada Lovelace",
                   "Grace Hopper",
                   "Marie Curie",
                   "Carl Friedrich Gauss",
                   "Nikola Tesla",
                   "Claude Shannon"];
      for (var i = 0; i < names.length; i++)
        Players.insert({name: names[i], score: Math.floor(Random.fraction()*10)*5});
    }
  });
}