Project Structure(Backend)

The updated dependencies in package.json file of backend will look like:

"dependencies": {
    "body-parser": "^1.20.2",
    "cors": "^2.8.5",
    "express": "^4.18.2",
    "mongoose": "^8.1.1"
}

Javascript

// blackjack-server/server.js
const express = require('express');
const mongoose = require('mongoose');
const cors = require('cors');
const bodyParser = require('body-parser');
 
const app = express();
const PORT = process.env.PORT || 5000;
 
app.use(cors());
app.use(bodyParser.json());
 
// Database connection configuration
mongoose.connect('mongodb://localhost:27017/blackjack', {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});
 
const cardSchema = new mongoose.Schema({
    suit: String,
    rank: String,
    value: Number,
});
 
const playerSchema = new mongoose.Schema({
    name: String,
    hand: [cardSchema],
    score: Number,
});
 
const gameSchema = new mongoose.Schema({
    deck: [cardSchema],
    player: playerSchema,
    dealer: playerSchema,
    winner: String, // New field to store the winner
});
 
 
const Card = mongoose.model('Card', cardSchema);
const Player = mongoose.model('Player', playerSchema);
const Game = mongoose.model('Game', gameSchema);
 
// Helper function to create a new deck
function createDeck() {
    const suits =
        ['Hearts', 'Diamonds', 'Clubs', 'Spades'];
    const ranks =
        ['2', '3', '4', '5', '6', '7', '8',
            '9', '10', 'J', 'Q', 'K', 'A'];
 
    const deck = [];
    for (const suit of suits) {
        for (const rank of ranks) {
            const card = new Card({
                suit: suit,
                rank: rank,
                value: rank ===
                    'A' ? 11 : isNaN(rank) ?
                    10 : parseInt(rank),
            });
            deck.push(card);
        }
    }
 
    return deck;
}
 
// Endpoint to start a new game
app.post('/game/start', async (req, res) => {
    try {
        const newDeck = createDeck();
 
        // Shuffle the deck (Fisher-Yates algorithm)
        for (let i = newDeck.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [newDeck[i], newDeck[j]] = [newDeck[j], 
            newDeck[i]];
        }
 
        const newGame = new Game({
            deck: newDeck,
            player: { name: 'Player', hand: [], 
            score: 0 },
            dealer: { name: 'Dealer', hand: [], 
            score: 0 },
        });
 
        // Deal the initial two cards to the player and the dealer
        newGame.player.hand.push(newGame.deck.pop());
        newGame.dealer.hand.push(newGame.deck.pop());
        newGame.player.hand.push(newGame.deck.pop());
        newGame.dealer.hand.push(newGame.deck.pop());
 
        // Update scores
        newGame.player.score = calculateScore(
            newGame.player.hand);
        newGame.dealer.score = calculateScore(
            newGame.dealer.hand);
 
        // Save the new game to the database
        await newGame.save();
 
        res.status(201).json(newGame);
    } catch (error) {
        console.error(error);
        res.status(500).send('Internal Server Error');
    }
});
 
// Endpoint to handle player hits
app.post('/game/hit', async (req, res) => {
    try {
        const gameId = req.body.gameId;
 
        // Fetch the game from the database
        const game = await Game.findById(gameId);
 
        // Draw a card from the deck and add it to the player's hand
        const drawnCard = game.deck.pop();
        game.player.hand.push(drawnCard);
 
        // Update the player's score
        game.player.score = calculateScore(
            game.player.hand);
 
        // Set the winner field
        game.winner = determineWinner(game.player.score,
            game.dealer.score);
 
        // Save the updated game to the database
        await game.save();
 
        res.json({ ...game.toObject(), 
            winner: game.winner });
    } catch (error) {
        console.error(error);
        res.status(500).send('Internal Server Error');
    }
});
 
app.post('/game/stand', async (req, res) => {
    try {
        const gameId = req.body.gameId;
 
        // Fetch the game from the database
        const game = await Game.findById(gameId);
 
        // Dealer draws cards until their score is 17 or higher
        while (game.dealer.score < 17) {
            const drawnCard = game.deck.pop();
            game.dealer.hand.push(drawnCard);
            game.dealer.score = calculateScore(
                game.dealer.hand);
        }
 
        // Set the winner field
        game.winner = determineWinner(game.player.score,
            game.dealer.score);
 
        // Save the updated game to the database
        await game.save();
 
        res.json({ ...game.toObject(), 
            winner: game.winner });
    } catch (error) {
        console.error(error);
        res.status(500).send('Internal Server Error');
    }
});
 
// Helper function to calculate the score of a hand
function calculateScore(hand) {
    let score = hand.reduce((total, card) =>
        total + card.value, 0);
 
    // Handle Aces (reduce value from 11 to 1 if necessary)
    hand.filter(card => card.rank === 'A')
    .forEach(_ => {
        if (score > 21) {
            score -= 10;
        }
    });
 
    return score;
}
 
// Helper function to determine the winner
function determineWinner(playerScore, 
    dealerScore) {
    if (playerScore > 21) {
        return 'Dealer'; // Player busts, dealer wins
    }
 
    if (dealerScore > 21) {
        return 'Player'; // Dealer busts, player wins
    }
 
    if (playerScore > dealerScore) {
        return 'Player'; // Player has a higher score
    } else if (playerScore < dealerScore) {
        return 'Dealer'; // Dealer has a higher score
    } else {
        return 'Draw'; // Scores are equal, it's a draw
    }
}
 
 
// Start the server
app.listen(PORT, () => {
    console.log(`Server is running on port ${PORT}`);
});

Steps to Run the backend:

Step 1: Navigate to blackjack-server root directory.

cd blackjack-server

Step 2: Run the server using following command.

node server.js

Blackjack Game using MERN Stack

In this tutorial, we’ll embark on a journey to create a fully functional Blackjack game using React for the frontend and Node for the backend. This engaging and interactive project will allow you to explore the realms of web development while learning how to implement key features of a classic card game.

Preview of Final Output: Let’s have a look at what our final project will look like:

Project Structure(Backend)

Javascript

Blackjack Game using MERN Stack

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