JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <p><strong>Console says:</strong></p>
    <code id="console"></code>
</div>

JavaScript

// Private variables in MooTools

// var console = console || { log: function() { document.id('console').innerHTML += Array.from(arguments).toString() + "<br />"; }}

var Private = function (){
    var secret = "cookies";
    
    return new (new Class({
        initialize: function(options) {
            console.log('class options are: ', options);
            console.log(this.method());
        },
        
        method: function(){
            return 'method!';
        },
        
        getSecret: function(){
            return secret;
        },
        
        setSecret: function(content){
           secret = content;
        }
    }))(Array.from(arguments));
};

// Instance 1
var test1 = new Private('option 1a', 'option 1b');

console.log( test1.getSecret() );
test1.setSecret('bacon');
console.log( test1.getSecret() );

// Instance 2
var test2 = new Private('option 2');
console.log( test2.getSecret() );