JSFiddle - React, Tailwind, and code Playground

HTML

Click on div 2 to affect div 1
<div id="div1">div 1</div>
<div id="div2">div 2</div>

CSS

#div1 { color: blue; }
#div2 { color: red; }

JavaScript

$.fn.observe = function(eventName, callback) {
    return this.each(function(){
        var el = this;
        $(document).on(eventName, function(){
            callback.apply(el, arguments);
        })
    });
}



$('#div2').on('click', function(e) {
    $(this).trigger('custom');
});

$('#div1').observe('custom', function(e) {
    $(this).css('color', 'green');
});