Shuffles array using pure js

arraySuffle.js

/**
 * Shuffles array
 * @param {Array} - array
 */
function shuffle(a) {
  let len = a.length;
  for (let i = len; i; i--) {
    let j = Math.floor(Math.random() * i);
    [a[i - 1], a[j]] = [a[j], a[i - 1]];
  }
}

let arr = ['1', '2', '3', '4', '5', '6', '7', '8', '9'];
shuffle(arr);
console.log(arr);
/* 
 Console log:
 ["7", "2", "8", "1", "5", "3", "9", "4", "6"]
*/