JSFiddle - React, Tailwind, and code Playground

JavaScript

function Foo() {
};

var x = new Foo();
Foo.prototype = Object.prototype;
var y = new Foo();

// true, true
document.write([ x instanceof Object, y instanceof Object ].join() + '<br/>');

// false, TRUE
document.write([ x.__proto__ === Object.prototype, y.__proto__ === Object.prototype ].join() + '<br/>');

// true
document.write(x.__proto__.__proto__ === Object.prototype);