blackjack.js

// Card Constructor
function Card(s, n) {
	var suit = s;
	var number = n;
	this.getNumber = function() {
		return number;
	};
	this.getSuit = function() {
		return suit;
	};
	this.getValue = function() {
		if (number > 10) {
			return 10;
		} else if (number === 1) {
			return 11;
		} else {
			return number;
		}
	};
}

function deal() {
	var randSuit = Math.floor(Math.random() * 4) + 1;
	var randNumber = Math.floor(Math.random() * 13) + 1;
	return new Card(randSuit, randNumber);
}

function Hand() {	
	var card1 = deal(), card2 = deal();
	var cards = [card1, card2];
	this.getHand = function() {
		return cards;
	};
	this.score = function() {
		var sum = 0;
		var aceCount = 0;
		for (var i = 0; i < cards.length; i++) {
			if (cards[i].getValue() === 11) {
				aceCount++;
			}
			sum += cards[i].getValue();
		}
		
		while (sum > 21 && aceCount > 0) {
			sum -= 10;
			aceCount--;
		}
		return sum;
	};
	this.printHand = function() {
		var string = "";
		for (var i = 0, length = cards.length; i < length; i++) {
			string += cards[i].getNumber() + " of suit " + cards[i].getSuit();
			string += (i === length - 1) ? "" : ", ";
		}
		return string;
	};
	this.hitMe = function() {
		cards.push(deal());
	};
}

function playAsDealer() {
	var hand = new Hand();
	while (hand.score() < 17) {
		hand.hitMe();
	}
	return hand;
}


function playAsUser() {
	var hand = new Hand();
	var decision = confirm("Your hand is " + hand.printHand() + ": Hit OK to hit (take another card) or cancel to stand");
	while(decision) {
		hand.hitMe();
		decision = confirm("Your hand is " + hand.printHand() + ": Hit OK to hit (take another card) or cancel to stand");
	}
	return hand;
}

function declareWinner(userHand, dealerHand) {
	var userScore = userHand.score();
	var dealerScore = dealerHand.score();

	if (userScore > 21) {
		if (dealerScore > 21) {
			return "You tie!";
		} else {
			return "You lose!";
		}
	} else {
		if (dealerScore > 21) {
			return "You win!";
		} else {
			if (userScore > dealerScore) {
				return "You win!";
			} else if (userScore === dealerScore) {
				return "You tie!";
			} else {
				return "You lose!";
			}
		}
	}	
}

function playGame() {	
	var dealerHand = playAsDealer();
	var userHand = playAsUser();
	var winnerMessage = declareWinner(userHand, dealerHand);
	console.log("Dealer has " + dealerHand.printHand());
	console.log("Dealer score is " + dealerHand.score());
	console.log("User has " + userHand.printHand());
	console.log("User score is " + userHand.score());
	console.log(winnerMessage);
}

playGame();