https://jamiebartlettdesign.com/wp-content/themes/cavalier/core/js/yith-wcwl-custom.js

1jQuery( document ).ready( function($){
2    var update_wishlist_count = function() {
3        $.ajax({
4            beforeSend: function () {
5
6            },
7            complete  : function () {
8
9            },
10            data      : {
11                action: 'update_wishlist_count'
12            },
13            success   : function (data) {
14            	if (data > 0) {
15                	$('.cavalier-wishlist-btn').append('<span class="wishlist-count">'+data+'</span>');
16                } else {
17	                $('.wishlist-count').remove();
18                }
19            },
20
21            url: yith_wcwl_l10n.ajax_url
22        });
23    };
24
25    $('body').on( 'added_to_wishlist removed_from_wishlist', update_wishlist_count );
26} );