up-river-andrew.js

(function() {
  const stats = {
    wins: 0,
    losses: 0,
  };

  const times = x => f => {
    if (x > 0) {
      f()
        times (x - 1) (f)
    }
  }
  const repeatOften = times(10000)

  function simulate() {
    const outCard = toRemove => card  => {
      return toRemove.value !== card.value || toRemove.suit !== card.suit;
    }

    const toShuffled = () => Math.random() - 0.5;

    const suits = [
      'Hearts',
      'Spades',
      'Clubs',
      'Diamonds',
    ];

    const values = [
      2,
      3,
      4,
      5,
      6,
      7,
      8,
      9,
      10,
      11, // jack
      12, // queen
      13, // king
      14, // ace
    ];

    let deck = values.reduce((acc, value) => {
      return [
        ...acc,
        ...suits.map(suit => ({
          value,
          suit,
        }))
      ];
    }, []).sort(toShuffled);

    const andrewsCard = {
      value: 9,
      suit: 'Hearts',
    };

    const trumpCard = {
      value: 2,
      suit: 'Clubs',
    };

    deck = deck.filter(outCard(andrewsCard));
    deck = deck.filter(outCard(trumpCard));

    const numberOfOpponents = 5;
    const opponentCards = deck.slice(0, numberOfOpponents);

    const toWinningCardWith = ({trump, led}) => (currentWinner, card, index) => {
      if (card.suit !== trump && card.suit !== led) { // ineligible to win
        return currentWinner;
      }

      if (card.suit === led) {
        if (currentWinner.suit === trump) {
          return currentWinner;
        }
        if (currentWinner.suit === led) {
          return currentWinner.value >= card.value ? currentWinner : card;
        }
      }

      if (card.suit === trump) {
        if (currentWinner.suit === trump) {
          return currentWinner.value >= card.value ? currentWinner : card;
        } else {
          return card;
        }
      }

    }

    const winningCard = [...opponentCards, andrewsCard]
      .reduce(toWinningCardWith({
        trump: trumpCard.suit,
        led: opponentCards[0].suit,
      }));

    const andrewLost = opponentCards.some(card => winningCard.suit === card.suit && winningCard.value === card.value);

    if (andrewLost) {
      stats.losses++;
    } else {
      stats.wins++;
    }
  }

  repeatOften(simulate);

  console.log(`Win Percentage: ${stats.wins / (stats.wins + stats.losses) * 100}%`);
})()