This code works as desired, but I am concerned about performance. The `_getSortPrefix()` function gets called on average `O(n log(n))` times for a list with `n` items, but it returns the same value every time. I think the original code is better -- only need to use preference instead of platform.

```
var _dirFirst       = PreferencesManager.get("sortDirectoriesFirst"),
        _sortPrefixDir  = _dirFirst ? "" : "0",
        _sortPrefixFile = _dirFirst ? "" : "1";
```