JSFiddle - React, Tailwind, and code Playground

HTML

<div id="log"></div>

JavaScript

String.prototype.doNothing = function() {
  return this;
};

document.getElementById('log').innerHTML = 
    [ 'typeof \'foo\'.donNothing(): ' + typeof 'foo'.doNothing()
      ,'typeof \'foo\': ' + typeof 'foo'
      ,'\'foo\'.constructor === String: '+ ('foo'.constructor === String)
      ,'\'foo\'.doNothing().constructor === String: '+ 
         ('foo'.doNothing().constructor === String)]
      .join('<br />');