dom-dispatched.js

// application shell
const mife = [];
window.registerMife = (name, call) => {
  mife.push({
    name,
    call,
  });
};

window.callMife = (target, msg) => {
  mife.filter(m => m.name === target).forEach(m => m.call(msg));
};

// microfrontend A
window.registerMife('A', msg => {
  //handle message;
});

// microfrontend B
window.callMife('A', {
  type: 'show_dialog',
  name: 'close_file'
});