quick sort using javascript

quicksort.js

/*
    Swap values using two index
    @param items {Array}
    @param firstIndex {Integer}
    @param secondIndex {Integer}
    @return 'undefined'
*/
var swap = function(items, firstIndex, secondIndex){
    var temp = items[firstIndex];
    items[firstIndex] = items[secondIndex];
    items[secondIndex] = temp;
    return;
};
/*
    partition
    
*/
var partition = function(items, left, right) {

    var pivot   = items[Math.floor((right + left) / 2)],
        i       = left,
        j       = right;


    while (i <= j) {

        while (items[i] < pivot) {
            i++;
        }

        while (items[j] > pivot) {
            j--;
        }

        if (i <= j) {
            swap(items, i, j);
            i++;
            j--;
        }
    }

    return i;
};

var quickSort = function(items, left, right) {

    var index;

    if (items.length > 1) {

        index = partition(items, left, right);

        if (left < index - 1) {
            quickSort(items, left, index - 1);
        }

        if (index < right) {
            quickSort(items, index, right);
        }

    }

    return items;
}


var arrToSort = [65,43,12,4,564,32,-5,-202, 45];
var result = quickSort(arrToSort, 0, arrToSort.length - 1);