function pivot(arr,start = 0 ,end = arr.length-1){ function swap(arr,i,j){ var temp = arr[i]; arr[i]=arr[j]; arr[j]=temp; } var pivot = arr[start]; var swapIdx = start; for(var i = start+1;i< arr.length;i++){ if(pivot>arr[i]){ swapIdx++; swap(arr,swapIdx,i); console.log(arr); } } swap(arr,start,swapIdx); return arr; } console.log(pivot([4,8,2,1,5,7,6,3]));