如何获得Firestore文档大小？

const firebase = require('firebase/app');
require('firebase/firestore');

// 初始化 Firebase 应用
const firebaseConfig = {
  // 你的 Firebase 配置信息
};

firebase.initializeApp(firebaseConfig);
const db = firebase.firestore();

async function getDocumentSize(collectionPath, documentId) {
  try {
    const docRef = db.collection(collectionPath).doc(documentId);
    const docSnapshot = await docRef.get();
    if (docSnapshot.exists) {
      const data = docSnapshot.data();
      const jsonString = JSON.stringify(data);
      const sizeInBytes = Buffer.byteLength(jsonString, 'utf8');
      console.log(`Document size: ${sizeInBytes} bytes`);
      return sizeInBytes;
    } else {
      console.log('No such document!');
    }
  } catch (error) {
    console.error('Error getting document:', error);
  }
}

// 使用示例
getDocumentSize('yourCollection', 'yourDocumentId');