JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/melanke/Watch.JS/master/src/watch.js"></script>

JavaScript

//defining our object no matter which way we want
var ex = {
    l1a: "bla bla",
    l1b: {
        l2a: "lo lo",
        l2b: "hey hey",
        l2c: null
    }
};

watch(ex, function (prop, action, difference, oldvalue){
    
    alert("prop: "+prop+"\n action: "+action+"\n difference: "+JSON.stringify(difference)+"\n old: "+JSON.stringify(oldvalue)+"\n ... and the context: "+JSON.stringify(this));    
    
});


ex.l1b.l2c = "new attr";