Algorithm to track Ace while shuffling deck of cards by splitting into two halves

trackingAce.js

function shuffleDeckAndReturnAcePosition(cardsCount, shufflesArr) {
  let cards = Array.from({ length: cardsCount }, (v, i) => i + 1);
  let acePosition = cards[cards.length - 1];
  let mid = Math.floor(cards.length / 2);
  for (let shuffle of shufflesArr) {
    // split cards into two decks
    let topHalf = cards.slice(0, mid);
    let bottomHalf = cards.slice(mid);
    // handle case for negative numbers by reversing top and bottom decks
    if (shuffle < 0) {
      [topHalf, bottomHalf] = [bottomHalf, topHalf];
      shuffle = Math.abs(shuffle);
    }
    // shuffle cards
    bottomDroppedCards = [];
    // drop cards one by one from bottom of each halves of the deck alternating between the halves until every card on the bottom has been dropped
    //
    for (let j = 0; j < shuffle; j++) {
      let droppedBottom = bottomHalf.pop();
      bottomDroppedCards.push(droppedBottom);
    }
    while (bottomHalf.length > 0) {
      bottomDroppedCards.push(topHalf.pop());
      bottomDroppedCards.push(bottomHalf.pop());
    }
    cards = bottomDroppedCards.concat(topHalf);
  }
  // find the position of the ace
  // reverse cards array
  cards = cards.reverse();
  acePosition = cards.indexOf(acePosition);
  return acePosition;
}

console.log(shuffleDeckAndReturnAcePosition(10, [1, -2]));