React Pivottable Grouping Sorting

In one of the forks of the main repository is the react-pivottable-grouping repository by jjagielka. Here is the link for the same: https://github.com/jjagielka/react-pivottable-grouping I want to implement sorting functionality to this nature of data that is when grouping is applied to react pivottable. I tried modifying the code a bit but couldnt achieve any concreet results.. Need help on this