dom-event.js

// microfrontend A
window.addEventListener('mife-a', e => {
  const { msg } = e.detail;
  //handle message;
});

// microfrontend B
window.dispatchEvent(new CustomEvent('mife-a', {
  detail: {
    type: 'show_dialog',
    name: 'close_file'
  }
}));