This is just for shuffling an array. It gives you a more shuffled array than using sort(). I got it from http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/ - I'm keeping it here just for backup purposes.

ArrayShuffle.js

/**
 * Shuffles array in place.
 *
 * @param {Array} a items The array containing the items.
 */
function shuffle(a) {
    var j, x, i;
    
    for (i = a.length; i; i--) {
        j = Math.floor(Math.random() * i);
        x = a[i - 1];
        a[i - 1] = a[j];
        a[j] = x;
    }
}

/**
 * Shuffles array in place. ES6 version.
 *
 * @param {Array} a items The array containing the items.
 */
function shuffle(a) {
    for (let i = a.length; i; i--) {
        let j = Math.floor(Math.random() * i);
        [a[i - 1], a[j]] = [a[j], a[i - 1]];
    }
}

/**
 * Shuffles a copy of an array and returns it.
 *
 * @param {Array} array The array to copy and shuffle.
 *
 * @returns {Array} The shuffled array.
 *
 * @see https://bost.ocks.org/mike/shuffle/
 */
function shuffle(array) {
  const a = [...array];
  
  let m = a.length;
  let t;
  let i;

  // While there remain elements to shuffle...
  while (m) {
    // Pick a remaining element...
    i = Math.floor(Math.random() * m--);

    // And swap it with the current element...
    t = a[m];
    a[m] = a[i];
    a[i] = t;
  }

  return a;
}