承诺后返回Firestore

<!-- 在HTML文件中引入Firebase SDK -->
<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>

// 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);

// 初始化Firestore
const db = firebase.firestore();

function getFirestoreData(collectionName) {
  return db.collection(collectionName).get(); // 返回一个承诺
}

// 使用示例
getFirestoreData('yourCollectionName')
  .then(snapshot => {
    snapshot.forEach(doc => {
      console.log(doc.id, '=>', doc.data());
    });
  })
  .catch(error => {
    console.error('Error getting documents: ', error);
  });

async function getFirestoreData(collectionName) {
  try {
    const snapshot = await db.collection(collectionName).get();
    snapshot.forEach(doc => {
      console.log(doc.id, '=>', doc.data());
    });
  } catch (error) {
    console.error('Error getting documents: ', error);
  }
}

// 使用示例
getFirestoreData('yourCollectionName');