Any API to extend?

I noticed that this datepicker is based on this one(https://github.com/amsul/pickadate.js), and modified to angularjs-based. but there are plenty of api of amsul's pickadate, so I'm wondering if there also are APIs we can use to custom the datepicker. I'm using this datepicker but the only way to change some format is to modify the angular-datepicker.js, it's not that friendly.
Thanks for the work and waiting for your reply