JavaScript:如何使用嵌套对象的变量名称创建嵌套对象？

Question

如何使用变量创建嵌套对象。在本例中，我有一个在全局上下文中创建的名为“手”的对象。现在我有 x 个玩家(在本例中为 3 个)，我为每个玩家发 5 张牌。

所以我希望手对象看起来像手[playerNum][cardInst][dealtCard]作为最终结果。我习惯了 Perl 哈希，这在 Perl 中非常简单。

但是，无论我如何尝试将元素放入手中，我都看不到卡片。请参阅下面的代码。 var 手 = {};在函数外部声明。我缺少什么？

function dealCards() {
    console.log("Dealing Cards\r\n");
    var numPlayers = 3;
    var curCard;

    for (i=0;i<5;i++) {
        var cardInst = i.toString();

        for (pn =0;pn<numPlayers;pn++){
            // get current value for pn and store it
            var playerNum = pn.toString();

            //get card off of game deck
            curCard = gameDeck.shift();

            //add card info to variables
            var dcardID = baseDeck[curCard].id;
            var dcardName = baseDeck[curCard].name;
            var dcardText = baseDeck[curCard].text;
            var dcardImg = "none";

            //create new card object
            var dealtCard = new card(dcardID,dcardName,dcardText,dcardImg);



            hands[playerNum][cardInst] = dealtCard;
            console.log("blah");
        }
    }
    console.log(hands);
}

function card(id,name,text,img){
    this.id = id;
    this.name = name;
    this.text = text;
    this.img = img;
}

var hands = {};



function dealCards() {
    console.log("Dealing Cards\r\n");
    var numPlayers = 3;
    var curCard;

    for (i=0;i<5;i++) {
        var cardInst = i.toString();

        for (pn =0;pn<numPlayers;pn++){
            // get current value for pn and store it
            var playerNum = pn.toString();

            //get card off of game deck
            curCard = gameDeck.shift();

            //add card info to variables
            var dcardID = baseDeck[curCard].id;
            var dcardName = baseDeck[curCard].name;
            var dcardText = baseDeck[curCard].text;
            var dcardImg = "none";

            //create new card object
            var dealtCard = new card(dcardID,dcardName,dcardText,dcardImg);



            hands[playerNum][cardInst] = dealtCard;
            console.log("blah");
        }
    }
    console.log(hands);
}

function card(id,name,text,img){
    this.id = id;
    this.name = name;
    this.text = text;
    this.img = img;
}

如有任何帮助，我们将不胜感激!

Z

Answer 1

有两件事； Hands[playerNum] 没有被初始化，并且函数 card() 没有返回值在添加之前尝试初始化内部对象(使用关键的playerNum)；

function dealCards() {
    console.log("Dealing Cards\r\n");
    var numPlayers = 3;
    var curCard;

    for (i=0;i<5;i++) {
        var cardInst = i.toString();

        for (pn =0;pn<numPlayers;pn++){
            // get current value for pn and store it
            var playerNum = pn.toString();

            //get card off of game deck
            curCard = gameDeck.shift();

            //add card info to variables
            var dcardID = baseDeck[curCard].id;
            var dcardName = baseDeck[curCard].name;
            var dcardText = baseDeck[curCard].text;
            var dcardImg = "none";

            //create new card object
            var dealtCard = new card(dcardID,dcardName,dcardText,dcardImg);

            if (hands[playerNum] === undefined){
                hands[playerNum] = {};
            }



            hands[playerNum][cardInst] = dealtCard;
            console.log("blah");
        }
    }
    console.log(hands);
}
function card(id,name,text,img){
    this.id = id;
    this.name = name;
    this.text = text;
    this.img = img;
    return this;
}

另外，我个人不喜欢使用“this dot property”的构造函数风格。返回新对象是一个更好的习惯，这样您就不会意外地从当前“this”上下文中捕获其他属性。

function card(id,name,text,img){
    return {
       id: id,
       name: name,
       text: text,
       img: img
    }
}