Quick Sort in Node js

var myArray = [3, 0, 2, 5, -1, 4, 1 ];

function quickSort(arr){
    var finalArray = [];
    if(arr.length <= 1){
        return arr
    }
    var midIndex = parseInt(arr/2);
    var pivot = arr.pop();
    var leftArray = [], rightArray = []; 
    for(var i= 0; i< arr.length; i++){
        if(arr[i] <= pivot){
            leftArray.push(arr[i]);
        }else{
            rightArray.push(arr[i])
        }
    }
   // console.log('left Array : ', leftArray, 'rightArray :', rightArray, 'pivot : ', pivot);
    return finalArray.concat(quickSort(leftArray), pivot, quickSort(rightArray));
    
}
console.log("Original array: " + myArray);
var sortedArray = quickSort(myArray);
console.log("Sorted array: " + sortedArray);