JSFiddle - React, Tailwind, and code Playground

JavaScript

var MyClass =function(arg) {
    this.init(arg);
};
MyClass.prototype = {
    init: function(arg) {
        // Do something with that arg
        this.someArg = arg;
    },
    myProperty: 'Hell world',
    someArg: null    
};

var myVar = new MyClass('Some arg');

console.log(myVar.myProperty);
console.log(myVar.someArg);