array.shuffle returns same item every time code example

Example 1: javascript randomly shuffle array

function randomArrayShuffle(array) {
  var currentIndex = array.length, temporaryValue, randomIndex;
  while (0 !== currentIndex) {
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }
  return array;
}
var alphabet=["a","b","c","d","e"];
randomArrayShuffle(alphabet); 
//alphabet is now shuffled randomly = ["d", "c", "b", "e", "a"]

Example 2: shuffle an array of numbers in javascript

let numbers = [5, 458 , 120 , -215 , 228 , 400 , 122205, -85411];
numbers = numbers.sort(function(){ return Math.random() - 0.5});
/* the array numbers will be equal for example to [120, 5, 228, -215, 400, 458, -85411, 122205]  */