React docs on useEffect

The docs have an example about using useEffect with cleanup, here.

If I carry out the sequence, then I would get
run effect -> subscribe to update from ChatApi -> setIsOnline -> cleanup -> run effect -> subscribe to update from ChatApi -> setIsOnline

I am unsure as to why this does not lead to an infinite loop without use of the dependency array?

One understanding / theory that I have is:
The first time the subscription cause setIsOnline(true). Next time (after one cycle of unsubscribe/effect), the setIsOnline gets argument as true and hence further update to the component does not occur. This is assuming that this form of setIsOnline does not re-render if the isOnline has not changed (it is still true).

I am curious as to why the piece of code is correct.

Here it is as copied from the useEffect documentation

import React, { useState, useEffect } from 'react';

function FriendStatus(props) {
  const [isOnline, setIsOnline] = useState(null);

  useEffect(() => {
    function handleStatusChange(status) {
      setIsOnline(status.isOnline);
    }
    ChatAPI.subscribeToFriendStatus(props.friend.id, handleStatusChange);
    // Specify how to clean up after this effect:
    return function cleanup() {
      ChatAPI.unsubscribeFromFriendStatus(props.friend.id, handleStatusChange);
    };
  });

  if (isOnline === null) {
    return 'Loading...';
  }
  return isOnline ? 'Online' : 'Offline';
}

Commencez par l’exemple lié de la documentation de useEffect et examinez la séquence décrite concernant la souscription, le nettoyage et setIsOnline. Déterminez si l’exemple nécessite une explication de son comportement lors des nouveaux rendus ou un exemple révisé, puis mettez à jour la documentation afin que le cycle de vie attendu de l’effet et les critères de fin soient explicites.