问题

我尝试过并调试了不同的方法，得出了这是问题的结论

const artistsCollectionRef = collection(db, "Artists");

onSnapshot(artistsCollectionRef, (snapshot) => {
snapshot.docChanges().forEach((change) => {
const updatedData = change.doc.data();
const eventId = updatedData.Events;

  const eventRef = doc(db, "Events", eventId);
  if (change.type === "modified") {
    updateDoc(eventRef, {
      Artist: updatedData.Name,
    });
  }
});

});

我正在使用 Firebase V10 和 Expo，如果这不是有帮助的话，对不起，这是我第一次在Stackoverflow上发帖。

我试图让当一个Firebase文档中的数据发生变化时，另一个文档中的数据也会发生变化，我还有更多的代码，但这段代码是问题所在。我正在使用useSnapshot来检查艺术家文档中是否发生了变化，然后它需要检查发生了什么变化，并根据变化更新事件文档。
```

<details>
<summary>英文:</summary>

I have tried and debugged different things and came to the conclusion that this is the problem


```
  const artistsCollectionRef = collection(db, &quot;Artists&quot;);

  onSnapshot(artistsCollectionRef, (snapshot) =&gt; {
    snapshot.docChanges().forEach((change) =&gt; {
      const updatedData = change.doc.data();
      const eventId = updatedData.Events;

      const eventRef = doc(db, &quot;Events&quot;, eventId);
      if (change.type === &quot;modified&quot;) {
        updateDoc(eventRef, {
          Artist: updatedData.Name,
        });
      }
    });
  });

I'm using Firebase V10 and Expo, sorry if this isn't helpful it's my first time posing on Stackoverflow.

I tried to make it so that when data changes in one Firebase document it also changes in another document, I have more code for this but this code is the problem. I'm using useSnapshot to check when a change is made in the artists document, then it needs to check what changed and update the event document based off of what changed

答案1

得分: 0

对eventRef变量存在问题，我无法确定问题出在哪里，因为它已经被定义了。但是我成功地通过以下方式解决了它：

const updatedData = change.doc.data();
const eventIds = updatedData.Events;

if (change.type === "modified") {
  for (const eventId of eventIds) {
    const eventRef = doc(db, "Events", eventId);
    await updateDoc(eventRef, {
      Artist: updatedData.Name,
    });
  }
}

const updatedData = change.doc.data();
      const eventIds = updatedData.Events;

      if (change.type === "modified") {
        for (const eventId of eventIds) {
          const eventRef = doc(db, "Events", eventId);
          await updateDoc(eventRef, {
            Artist: updatedData.Name,
          });
        }
      }