QuickSort-JavaScript

function partition(start, end, array){

	let firstGreater = start;
	let increment = start;
	let pivotIndex = end;
	let pivot = array[pivotIndex];

	while(increment < pivotIndex){
			if(array[increment] > pivot){        
				increment++;        
			}else{
				swap(increment, firstGreater, array);
				firstGreater++;
				increment++;      
			}
	}
	swap(pivotIndex, firstGreater, array);
	return firstGreater;
}

function swap(i,j,arr){  
  if(i==j){
    return;
  }
  let ii = arr[i];
  arr[i] = arr[j];
  arr[j] = ii;  
}

function shiftPivotToTheRight(start, end,array){
	var pivot = start +  Math.floor((end - start)/2);
	swap(pivot, end, array);
}



function sortArray(start, end, array){  
  if(end - start <1){
    return array;
  }
  shiftPivotToTheRight(start, end,array);
  //  debugger;
  var pivot = partition(start, end, array);
;
  sortArray(start, pivot - 1, array);
  sortArray(pivot +1, end, array);
  return array;
}

function quickSort( array) {
  sortArray(0, array.length -1, array)
  return array;
}

var res = quickSort([1,4,3,6,5,77,3]);
var res = quickSort([1, 4, 2, 8, 345, 123, 43, 32, 5643, 63, 123, 43, 2, 55, 1, 234, 92]);
var res = quickSort( [1,4,2,1]);
console.log('res', res);