如何将用户的displayName添加到Firestore数据库集合条目？

// 初始化 Firebase
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);

// 获取 Firestore 实例
const db = firebase.firestore();

// 获取当前用户
const user = firebase.auth().currentUser;

if (user) {
  // 用户存在，获取 displayName
  const displayName = user.displayName;

  // 添加 displayName 到 Firestore 集合
  db.collection('users').doc(user.uid).set({
    displayName: displayName,
    createdAt: firebase.firestore.FieldValue.serverTimestamp()
  })
  .then(() => {
    console.log("Document successfully written!");
  })
  .catch((error) => {
    console.error("Error writing document: ", error);
  });
} else {
  console.log("No user is currently signed in.");
}

const admin = require('firebase-admin');
const serviceAccount = require('./path/to/serviceAccountKey.json');

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "YOUR_DATABASE_URL"
});

const db = admin.firestore();

async function addUserDisplayName(userId, displayName) {
  try {
    await db.collection('users').doc(userId).set({
      displayName: displayName,
      createdAt: admin.firestore.FieldValue.serverTimestamp()
    });
    console.log("Document successfully written!");
  } catch (error) {
    console.error("Error writing document: ", error);
  }
}

// 示例调用
addUserDisplayName('USER_ID', 'John Doe');