BlackJack, a command line JavaScript application

1. Running this application

• git clone this repo.
• Open up the app in VSCode or a similar IDE.
• run npm install to install any dependencies this project uses.
• run node black-jack.js and have some BlackJack fun. A♠️, K♥️

2. Dependencies

require package is used in this application to read in user input.

npm install require

const readline = require('readline');

const r1 = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

r1.question('Do you want to `hit` or `stand`?', (answer) => {
  console.log(`You entered ${answer}`); // You entered hit
})

3. Main classes

Card

class Card {
  constructor(value, suit) {
    this.value = value;
    this.suit = suit;
  }

  cardValue() {
    if (this.value > 1 || this.value < 11) {
      return this.value;
    }
    if (this.value === "J" || this.value === "Q" || this.value === "K") {
      return 10;
    }
    return 11; // default for Ace
  }
}

Deck

class Deck {
  // create 52 cards
  constructor(aceValue) {
    let cards = [];
    const suits = ["♥️", "♦️", "♣️", "♠️"];
    for (let value = 2; value < 11; value++) {
      for (const suit of suits) {
        const card = new Card(value, suit);
        cards.push(card);
      }
    }
    const highCards = ["J", "Q", "K", "A"];
    for (const highCard of highCards) {
      for (const suit of suits) {
        const card = new Card(highCard, suit);
        cards.push(card);
      }
    }
    console.log(cards);
    return cards;
  }
}

BlackJack

class BlackJack {
  constructor() {
    this.cards = new Deck();
    this.score = 0;
    console.log("Welcome to BlackJack.");
    console.log(`The deck has ${this.cards.length} cards.`);
  }

  hasCards() {
    return this.cards.length === 0;
  }

  hit() {
    const card = this.cards[Math.floor(Math.random() * this.cards.length)]; 
    const index = this.cards.indexOf(card); 
    this.cards.splice(index, 1); 
    console.log(
      `${this.cards.length} cards left, ${card.value}${
        card.suit
      } was removed with value ${card.cardValue()}.`
    );
    const gamePlayStatus = this.checkScore(card);
    return { card: card, gamePlayStatus: gamePlayStatus, score: this.score };
  }

  checkScore(card) {
    this.score += card.cardValue();
    console.log(this.score);
    if (this.score === 21) {
      return "blackJack";
    } else if (this.score > 21) {
      return "bust";
    } else {
      return "continue";
    }
  }

  getScore() {
    return this.score;
  }

  computerScore() {
    const score = Math.floor(Math.random() * (21 - 18) + 18);
    return score;
  }

  stand() {
    const playerScore = blackJack.getScore();
    const computerScore = blackJack.computerScore();
    const playerScoreDiff = 21 - playerScore;
    const computerScoreDiff = 21 - computerScore;
    if (computerScore > 21) {
      console.log(
        `You won with ${playerScore} and the computer lost with ${computerScore}`
      );
    } else {
      if (computerScoreDiff === playerScoreDiff) {
        console.log(
          `Tie!, computer score is ${computerScore} and your score is ${playerScore}`
        );
      } else if (computerScoreDiff < playerScoreDiff) {
        console.log(
          `You lost with ${playerScore} and the computer won with ${computerScore}`
        );
      } else {
        console.log(
          `You won with ${playerScore} and the computer lost with ${computerScore}`
        );
      }
    }
  }
}

4. Game play start

const blackJack = new BlackJack();

const r1 = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

const gamePlay = function () {
  r1.question("Do you want to `hit` or `stand`?", (answer) => {
    if (answer === "hit") {
      const result = blackJack.hit();
      if (result.gamePlayStatus === "blackJack") {
        console.log(`Woohoo BlackJack!!!!`);
        return r1.close();
      }
      if (result.gamePlayStatus === "bust") {
        console.log(`Better luck next time.`);
        return r1.close();
      }
    }
    if (answer === "stand") {
      blackJack.stand();
      return r1.close();
    }
    gamePlay();
  });
};

gamePlay();

Bonus features

If cloning this repo or working on the BlackJack implementation, please feel free to add additional BlackJack features like being able to place bets and splitting cards. Happy coding 🥳