JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/melanke/Watch.JS/master/src/watch.js"></script>
<input type="button" id="button" value="obj.cont++"/>

JavaScript

$(function(){

    var obj = {cont: 0};
    
    watch(obj, "cont", function(){
        alert("obj.cont = "+obj.cont);
    });
    
    $("#button").click(function(){
        obj.cont++;
    });
});