Sorting javascript objects in array by properties (angularjs filter)

I'm trying to sort an array of javascript objects by their properties for an angularjs application. I need to be able to sort by Numbers and Strings.

So far i have expanded the filter from Armin provided in this thread to sort numbers and strings (see code below).

What i am still missing is the ability to give a nested property (like user.surname) to the filter. It should be dynamic, so that i would be able to provide any depth of nested properties to it. Is there a way to do this?

Here's my filter code:

angular.module('app')
    .filter('orderObjectBy', function(){
        return function(input, filterBy) {
            if (!angular.isObject(input)) return input;

            var attribute = filterBy;
            var reverse = false;

            if (filterBy.substr(0,1) == '-') {
                attribute = filterBy.substr(1);
                reverse = true;
            }

            var array = [];
            for(var objectKey in input) {
                array.push(input[objectKey]);
            }

            if (parseInt(array[0][attribute])) {
                array.sort(function(a, b){
                    a = parseInt(a[attribute]);
                    b = parseInt(b[attribute]);
                    return a - b;
                });
            } else {
                array.sort(function (a,b) {
                    if (a[attribute] < b[attribute]) {
                        return -1;
                    } else if (a[attribute] > b[attribute]) {
                        return 1;
                    } else {
                        return 0;
                    }
                });
            }

            if (reverse) {
                return array.reverse();
            } else {
                return array;
            }

        }
    });