Firebase | collectionGroup查询问题

import firebase from 'firebase/app';
import 'firebase/firestore';

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
  appId: "YOUR_APP_ID"
};

firebase.initializeApp(firebaseConfig);

const db = firebase.firestore();

// 查询所有名为 "items" 的集合中的文档
db.collectionGroup('items')
  .where('category', '==', 'electronics')
  .get()
  .then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
      console.log(doc.id, ' => ', doc.data());
    });
  })
  .catch((error) => {
    console.log('Error:', error);
  });