old_contents: import jsdom, {JSDOM} from 'jsdom';
  const dom = new JSDOM('<!DOCTYPE html>');
  global.window = dom.window;
  global.document = dom.window.document;
new_contents: import jsdom, {JSDOM} from 'jsdom';
  const dom = new JSDOM('<!DOCTYPE html>');
  global.window = dom.window;
  global.document = dom.window.document;
  global.navigator = dom.window.navigator;
subject: add navigator