如何将来自Cloud Firestore的异步数据保存为变量？

<script src="https://www.gstatic.com/firebasejs/9.0.2/firebase-app.js"></script>
<script src="https://www.gstatic.com/firebasejs/9.0.2/firebase-firestore.js"></script>

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();

function getDataFromFirestore() {
  return new Promise((resolve, reject) => {
    db.collection("your_collection_name").get()
      .then((querySnapshot) => {
        const data = [];
        querySnapshot.forEach((doc) => {
          data.push(doc.data());
        });
        resolve(data);
      })
      .catch((error) => {
        reject(error);
      });
  });
}

// 调用函数并保存数据到变量
getDataFromFirestore()
  .then((data) => {
    // 在这里可以对获取到的数据进行处理或使用
    console.log(data);
  })
  .catch((error) => {
    console.error(error);
  });