Flash: A better sortOn() function

The Array.sortOn() function in ActionScript 2 and ActionScript 3 has a bug in it that causes you to be unable to use it to sort on Object properties that use a Getter function rather than a native property. So, for instance if the property you want to sort on is something like this...

public function get sortValue()

{

     return someNumber;

}

...and you want to call sortOn like this...

someArray.sortOn("sortValue");

...it won't sort correctly. From what I can tell, it seems to sort okay as long as the numbers returned by the getter function are under ten. After that, it will sort by the first digit of the number, so 1 == 10 == 11 == 12 == 13 etc. Anyway, getting around this isn't too hard, you just have to make your own sortOn prototype, like this:

Array.prototype.sortOnNumber = function(sortOn:String) {
    var index:Object;
    var j:Number;

    for (var i:Number=1;i<this.length;i++)
    {
        index = this[i];
        j = i;
        while ((j > 0) && (Number(this[j-1][sortOn]) > Number(index[sortOn])))
        {
            this[j] = this[j-1];
              j = j - 1;
        }
        this[j] = index;
    }

}

Type casting the comparison objects to Number() seems to solve the problem. This particular sort function uses an insertion sort algorithm. Implementing other algorithms is up to you.

References

http://livedocs.adobe.com/flash/8/main/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Parts&file=00001916.html

http://board.flashkit.com/board/showthread.php?t=740083

http://linux.wku.edu/~lamonml/algor/sort/insertion.html