quicksort.js

var quickSort = function(arr, key, reverse) {

    reverse = reverse || false

    if (arr.length <= 1) {
        return arr;
    }

    var less = Array(),
        greater = Array();

    var pivotIndex = Math.floor(arr.length / 2);
    var pivot = arr.splice(pivotIndex, 1)[0];

    for (var x = 0; x < arr.length; x++) {
        if (
            (!key && !reverse && ( (arr[x] < pivot) || (arr[x] == pivot && x < pivotIndex) )) ||
            (key && !reverse && ( (arr[x][key] < pivot[key]) || (arr[x][key] == pivot[key] && x < pivotIndex) )) ||
            (!key && reverse && ( (arr[x] > pivot) || (arr[x] == pivot && x > pivotIndex) )) ||
            (key && reverse && ( (arr[x][key] > pivot[key]) || (arr[x][key] == pivot[key] && x > pivotIndex) )) ) {
            less.push(arr[x]);
        } else {
            greater.push(arr[x]);
        }
    }

    return quickSort(less, key).concat([pivot], quickSort(greater, key));
};