function shuffle(array) {
  let currentIndex = array.length,  randomIndex;

  // While there remain elements to shuffle...
  while (currentIndex != 0) {

    // Pick a remaining element...
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex--;

    // And swap it with the current element.
    [array[currentIndex], array[randomIndex]] = [
      array[randomIndex], array[currentIndex]];
  }

  return array;
}

// Used like so
var arr = [2, 11, 37, 42];
shuffle(arr);
console.log(arr);

let items = [1,25,"JavaScript",69,"css","34","keep coding","html"];
console.log(items)

//shuffle array
function shuffle(arr){
  for(let i =arr.length-1;i>0;i--){
    const j = Math.floor(Math.random() * (i+1));
    [arr[i],arr[j]] = [arr[j],arr[i]];
  }
  return arr
}
console.log(shuffle(items))

//shuffle selected index 
const  itemToShuffle = items.slice(3,7);
console.log(shuffle(itemToShuffle))

//items after shuffling item from index 3 to 7
items = [items[0],items[1],items[2],...itemToShuffle,items[7]]
console.log(items)