如何在firebase数据库中成功计算子数据库中的值

{
  "users": {
    "user1": {
      "score": 100
    },
    "user2": {
      "score": 200
    }
  }
}

// Import the functions you need from the SDKs you need
import { initializeApp } from "https://www.gstatic.com/firebasejs/9.6.1/firebase-app.js";
import { getDatabase, ref, onValue } from "https://www.gstatic.com/firebasejs/9.6.1/firebase-database.js";

// Your web app's Firebase configuration
const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  databaseURL: "YOUR_DATABASE_URL",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
  appId: "YOUR_APP_ID"
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);
const database = getDatabase(app);

const usersRef = ref(database, 'users');
let totalScore = 0;

onValue(usersRef, (snapshot) => {
  let scores = snapshot.val();
  if (scores) {
    for (let userId in scores) {
      totalScore += scores[userId].score;
    }
    console.log('Total Score:', totalScore);
  } else {
    console.log('No data available');
  }
});

onValue(usersRef, (snapshot) => {
  // ... existing code ...
}, (error) => {
  console.error('Error reading data:', error);
});