use CLRS RANDOMIZE-IN-PLACE

array.shuffle.js

Array.prototype.shuffle = function shuffle() {
  for (let i = 0; i < this.length; i++){
    let randomI = Math.floor(Math.random() * (this.length - i)) + i;
    let temp = this[i];
    this[i] = this[randomI];
    this[randomI] = temp;
  }
  return this;
}