JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">

</div>

JavaScript

var ProxiedType = class {};
var notAProxiedType = new class {}();

var obj = new Proxy(notAProxiedType, {
  getPrototypeOf: function(key) {
    return ProxiedType.prototype;
  }
});


document.getElementById('foo').textContent = obj instanceof ProxiedType;