snapshot.js

const getComments = () => {
  return onSnapshot(collection(db, 'comments'), (value) => {
    const comments = value.docs.reduce((acc, item) => {
      if (id.id === item.data().coinId) {
        acc.push({ ...item.data(), id: item.id })
      }
      return acc;
    }, [])
    setComments(comments);
  });
};


useEffect(() => {
  if (!toggle) {
    return;
  }
  
  const unsub = getComments();
  return unsub;
}, [toggle]);