javascript - 为什么这个 if 语句在不应该为真时却总是为真？

Question

我正在制作一款游戏，目标是使用普通的牌组获得 4 对。当我提示玩家想要询问另一位玩家哪个卡牌值时，else if (playerArray[turn].cards.indexOf(card) == -1) 始终评估为 true，即使卡变量包含卡数组的值。这对我来说根本没有意义，我一直在思考如何解决这个问题。非常感谢任何建议。

var playerArray = [];       //Holds the player objects
var turn = 0;               //Keeps track of whose turn it is
var wrongCard = true;
var card = askCard(player); //Prompt to get a card value

function askCard(player) {

    var whichCard = prompt('The deck has: ' + deck.length + ' cards left in it.\n'
    + 'Your current cards are: ' + playerArray[turn].cards.join(' - ') + '\n'
    + player + ', all your:');

    return whichCard;
}

    while (wrongCard) { //Run as long as the card input is wrong

        if (card < 1 || card > 13) { //If card value is not between 1-13
            card = askCard(player);
        }

        //If the asked card doesn't exist in the current player's cards array
        else if (playerArray[turn].cards.indexOf(card) == -1) { //ALWAYS TRUE, WHY?
            card = prompt('The deck has: ' + deck.length + ' cards left in it.\n' +
                          'Your current cards are: ' + playerArray[turn].cards.join(' - ') 
                          + '\n' + player + ', all your:');
        }

        else {
            wrongCard = false; //Jump out of loop
        }
    }

Answer 1

使用

playerArray[turn].cards.indexOf(parseInt(card,10)) == -1)