In this post, I will be building a deck of cards in JavaScript, that can be used for future projects or future games, such as Blackjack. It's a super quick project, and can be done in less than 100 lines of code. I will be implementing as many card related functions as I can, such as shuffling a deck, grabbing a card from the top or bottom and creating a new deck of cards.
If you are new to JavaScript, I highly recommend Web Design with HTML, CSS, JavaScript and jQuery, which can definitely get you up and running pretty quickly with JavaScript.
Deck of Cards
Project: Deck of cards
Language: JavaScript
Estimated Completion: 1 hour
Overview
A deck of traditional playing cards is composed of 4 sets of 13 sequential numbered cards. A, 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, and K. Each card in the set belongs to a particular suit: Hearts, Spades, Clubs and Diamonds. The deck will consist of an Array of objects with a function to render each card graphically.
Variable declarations
Declare the following variables in order to get started.
var deck = new Array();
var suits = ["spades", "diamonds", "clubs", "hearts"];
var values = ["A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K"];
The deck variable is an array that will hold the card objects. The second variable suits is an array of card suites that we will use as a lookup table. And our 3rd variable values will hold all the possible values that a card can have.
Create The Deck
In order to create the deck, we're going to pair up each suit from the array above, with each possible value also from the array declared above. We're going to create a new card object with the corresponding value and suit and that object will be added that to the deck array.
function getDeck()
{
var deck = new Array();
for(var i = 0; i < suits.length; i++)
{
for(var x = 0; x < values.length; x++)
{
var card = {Value: values[x], Suit: suits[i]};
deck.push(card);
}
}
return deck;
}
This function will populate the deck array with 52 card objects.
Shuffling the card deck
Next up we need a function to shuffle the deck. For this, we are going to pick 2 random locations on the deck, and then switch their values around. We will be doing this about 1000 times per shuffle, which is way more than I could do manually, so it should be good enough to generate seemingly random deck.
function shuffle()
{
// for 1000 turns
// switch the values of two random cards
for (var i = 0; i < 1000; i++)
{
var location1 = Math.floor((Math.random() * deck.length));
var location2 = Math.floor((Math.random() * deck.length));
var tmp = deck[location1];
deck[location1] = deck[location2];
deck[location2] = tmp;
}
}
At this point, the deck array should contain 52 objects in a random order. But it's funner to see it than to hear me talk about it, so my next trick, I'm going to make the cards appear.
function renderDeck()
{
document.getElementById("deck").innerHTML = "";
for(let i = 0; i < deck.length; i++)
{
let card = document.createElement("div");
let value = document.createElement("div");
let suit = document.createElement("div");
card.className = "card";
value.className = "value";
suit.className = "suit " + deck[i].Suit;
value.innerHTML = deck[i].Value;
card.appendChild(value);
card.appendChild(suit);
document.getElementById("deck").appendChild(card);
}
}
I gave each card a child with the className of its corresponding suit. And used the following sprite to grab the icons from.
At this point, we have the functions to create a new deck of cards, shuffle them, and draw them out onto the screen. It looks something like the following.
Version 2: Rendering
A cleaner way render the cards (at least to me) is a method that I used in my blackjack game, in which I use HTML entities instead of images.
function renderDeck()
{
document.getElementById('deck').innerHTML = '';
for(var i = 0; i < deck.length; i++)
{
var card = document.createElement("div");
var icon = '';
if (deck[i].Suit == 'hearts')
icon='?';
else if (deck[i].Suit == 'spades')
icon = '?';
else if (deck[i].Suit == 'diamonds')
icon = '?';
else
icon = '?';
card.innerHTML = deck[i].Value + '' + icon;
card.className = 'card';
document.getElementById("deck").appendChild(card);
}
}
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Version1.zip
Version2.zip
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Walter Guevara is a Computer Scientist, software engineer, startup founder and currently mentors for a coding bootcamp. He has been creating software for the past 15 years.