JSFiddle - React, Tailwind, and code Playground

HTML

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

JavaScript

var proto = {
  nonEnumerable: 'This property should not show up in for in loops',
}

var a = Object.create(proto) 
a.one = 1;
a.two = 2;
a.three = 3;

var log = document.getElementById('log');
for (var i in a) {
    log.innerHTML += i+": "+a[i]+"<br>\n";
}

// test native object, too!
var dol = log.classList;
for (var i in dol) {
    log.innerHTML += i+": "+a[i]+"<br>\n";
}