react firestore快照不是函数

// 错误的调用方式
const data = snapshot(); // 这里会报错

// 正确的调用方式
const data = snapshot.docs.map(doc => doc.data());

if (snapshot instanceof firebase.firestore.QuerySnapshot) {
  const data = snapshot.docs.map(doc => doc.data());
} else {
  console.error('snapshot is not a QuerySnapshot');
}

npm update firebase react-firestore

import React, { useEffect, useState } from 'react';
import firebase from 'firebase/app';
import 'firebase/firestore';

const MyComponent = () => {
  const [data, setData] = useState([]);

  useEffect(() => {
    const fetchData = async () => {
      const db = firebase.firestore();
      const query = db.collection('myCollection');

      query.onSnapshot(snapshot => {
        const data = snapshot.docs.map(doc => doc.data());
        setData(data);
      }, error => {
        console.error('Error fetching data: ', error);
      });
    };

    fetchData();
  }, []);

  return (
    <div>
      {data.map((item, index) => (
        <div key={index}>{JSON.stringify(item)}</div>
      ))}
    </div>
  );
};

export default MyComponent;