JSFiddle - React, Tailwind, and code Playground

JavaScript

var MyClass = (function(){

        var static_var = 1;

        var MyClass = function ( callback ) {

            var privateVar;
            var privateFn = function(){ alert('Im private!'); };

            this.someProperty = 5;
            this.someFunction = function () {
                alert('Im public!');
            };
            this.say = function() {
                alert('Num ' + this.someProperty);
                callback();
            }
            this.alter = function() {
                this.someProperty ++;
            }
        };

        return MyClass;

    })();

    TheClass = new MyClass(function() {
        alert('Event!');
    });

    TheClass.say();