如何从Firestore Node.js中获取时间戳格式的数据

npm install firebase-admin
npm install @google-cloud/firestore

const admin = require('firebase-admin');
const firestore = require('@google-cloud/firestore');

admin.initializeApp({
  credential: admin.credential.applicationDefault()
});

const db = admin.firestore();

const docRef = db.collection('collectionName').doc('documentId');

docRef.get()
  .then((doc) => {
    if (doc.exists) {
      const data = doc.data();
      const timestamp = data.timestampField.toDate();
      console.log(timestamp);
    } else {
      console.log('No such document!');
    }
  })
  .catch((error) => {
    console.log('Error getting document:', error);
  });