Logs any properties that have been added to the Window object.

addedWindowProps.js

const i = document.createElement('iframe');
i.style.display = 'none';

document.body.appendChild(i);

const obj = {};
Object.keys(window)
    .filter(value => Object.keys(i.contentWindow).indexOf(value) < 0)
    .forEach(key => obj[key] = window[key]);

i.parentNode.removeChild(i);

console.log(obj);