Javascript error

I am getting the following javascript error on my site:

Uncaught TypeError: Cannot read property ‘i’ of undefined
http://swinginatthesavoy.com/wp-content/plugins/page-scroll-to-id/js/jquery.malihu.PageScroll2id.js?ver=1.6.1 line 2

It is related to this line in jquery.malihu.PageScroll2id.js?ver=1.6.1:

_currentTarget: function(a) {
            var n = s["target_" + a.data(_).i];

where a is defined as follows:

a = [section#guests._mPS2id-t.mPS2id-target, context: document, selector: "#guests"]

I don’t quite understand the a.data(_).i syntax, so I don’t know how to debug/fix this.

Any advice would be appreciated.

https://ww.wp.xz.cn/plugins/page-scroll-to-id/