shuffle 1.0.0

/**
 * Makes a shuffled copy of an array, leaving the original as it was. Every
 * order is equally likely (a Fisher–Yates shuffle).
 * @template T
 * @param {ArrayLike.<T>|Iterable.<T>} arr
 *    The array, or array-like or iterable object (such as a string or a Set),
 *    to shuffle.
 * @param {boolean} [useCrypto=false]
 *    If `true`, uses `crypto.getRandomValues()` instead of `Math.random()`, so
 *    the order can't be predicted.
 * @returns {Array.<T>}
 *    A new array with the same items in a random order.
 *
 * @example <caption>Shuffling a deck</caption>
 * const deck = ['A♠', 'K♠', 'Q♠', 'J♠'];
 * shuffle(deck);
 * // → a new order, like ['Q♠', 'A♠', 'J♠', 'K♠'] (deck is unchanged)
 *
 * @example <caption>Shuffling the letters of a word</caption>
 * shuffle('table').join('');
 * // → a jumble like 'ebalt'
 */
function shuffle(arr, useCrypto) {
  const copy = Array.from(arr);
  for (let i = copy.length - 1; i > 0; i--) {
    const j = random(0, i + 1, { useCrypto, returnInt: true });
    [copy[i], copy[j]] = [copy[j], copy[i]];
  }
  return copy;
}