JSFiddle - React, Tailwind, and code Playground

JavaScript

(function(window){
   "use strict"
   var App = function ( selector ) {
       this.selector = selector;
       this.init();
   };

   App.prototype = {
       constructor: App,
      init: function () {
         console.log(this.selector)
         console.log('init', this);
      },
   }

   window.app = function( selector ) {
       return new App( selector );
   };

})(window)

app('something')