如何在firestore中知道集合何时发生了更改？

// 引用目标集合
const collectionRef = db.collection('your-collection');

// 添加监听器
const unsubscribe = collectionRef.onSnapshot((snapshot) => {
  snapshot.docChanges().forEach((change) => {
    if (change.type === 'added') {
      // 处理文档添加
      console.log('Added document: ', change.doc.data());
    }
    if (change.type === 'modified') {
      // 处理文档修改
      console.log('Modified document: ', change.doc.data());
    }
    if (change.type === 'removed') {
      // 处理文档删除
      console.log('Removed document: ', change.doc.data());
    }
  });
});

// 停止监听
// unsubscribe();