text: {
    if (!Object.prototype.hasOwnProperty.call(mountAt, topListenersIDKey)) {
      mountAt[topListenersIDKey] = reactTopListenersCounter++;
      alreadyListeningTo[mountAt[topListenersIDKey]] = {};
    }
  
    return alreadyListeningTo[mountAt[topListenersIDKey]];
  }
  