Custom handlers Example Code
add-message-item.js
$(function() {
Shiny.addCustomMessageHandler('add-message-item', function(message) {
// since we do not re-render the dropdown, we must update its item counter
var $items = $('.dropdown-menu').find('.dropdown-item').length;
$('.dropdown-item.dropdown-header').html($items + ' Items');
$('.nav-item.dropdown').find('.navbar-badge').html($items);
// convert string to HTML
var itemTag = $.parseHTML(message)[0];
$(itemTag).insertAfter($('.dropdown-item.dropdown-header'));
});
});