《javascript权威指南》第9章 例9-8源码

//创建一个新的枚举类型
//不能使用它来创建该类型的新实例
function Enumeration(nameToValues){
    var Enumeration = function(){throw "Can't Instantiate Enumerations";};

    var proto = Enumeration.prototype = {
        constructor: Enumeration,
        toString: function(){return this.name;},
        valueOf: function(){return this.value;},
        toJSON: function(){return this.name;}
    };

    Enumeration.values = [];

    for(name in nameToValues){
        var e = Object.create(proto);
        e.name = name;
        e.value = nameToValues[name];
        Enumeration[name] = e;
        Enumeration.values.push(e);
    }

    Enumeration.foreach = function(f, c){
        for(var i = 0; i < this.values.length; i++) f.call(c, this.values[i]);
    };

    return Enumeration;
}

function Card(suit, rank){
    this.suit = suit;
    this.rank = rank;
}

Card.Suit = Enumeration({Clubs:1, Diamonds:2, Hearts:3, Spades: 4});
Card.Rank = Enumeration({Two:2,Three:3,Four:4,Five:5,Six:6,
                         Seven:7,Eight:8,Nine:9,Ten:10,
                         Jack:11,Queen:12,King:13,Ace:14});

Card.prototype.toString = function(){
        return this.rank.toString() + " of " + this.suit.toString();
};

Card.prototype.compareTo = function(that){
        if(this.rank < that.rank) return -1;
        if(this.rank > that.rank) return 1;
        return 0;
};

Card.orderBySuit = function(a, b){
    if(a.suit < b.suit) return -1;
    if(a.suit > b.suit) return 1;
    if(a.rank < b.rank) return -1;
    if(a.rank > b.rank) return 1;
    return 0;
}

function Deck(){
    var cards = this.cards = [];
    Card.Suit.foreach(function(s){
                        Card.Rank.foreach(function(r){
                                             cards.push(new Card(s, r));
                                         });
                     });
}

Deck.prototype.shuffle = function(){
    var deck = this.cards, len = deck.length;
    for(var i = len - 1; i > 0; i--){
        var r = Math.floor(Math.random() * (i + 1)),
            temp;
        temp = deck[i], deck[i] = deck[r], deck[r] = temp;
    }

    return this;
}

Deck.prototype.deal = function(n){
    if(this.cards.length < n) throw "Out of cards";
    return this.cards.splice(this.cards.length - n, n);
}

var deck = (new Deck()).shuffle();
var hand = deck.deal(13).sort(Card.orderBySuit);

console.log(hand);