Extensions: simple heuristic way to check if the user is logged in (in any page)

isPageLoggedIn.js

export default function isPageLoggedIn() {
  return Boolean(Array.from(document.body.querySelectorAll('a, button')).find(el => {
    return el.innerText && el.innerText.match(/sign out|signout|log out|logout/i) !== null;
  }));
}