app/assets/javascripts/table_of_contents.js
/* global Blacklight */
Blacklight.onLoad(function() {
$('.blacklight-toc_search').on('show.bs.collapse hide.bs.collapse', function(){
var _this = $(this);
var linkText = $(_this).find('span');
$(linkText).text(linkText.text() == 'Show' ? 'Hide' : 'Show' );
});
});