ref2.orderByChild 不是函数

Question

一段时间后，我试图从 firebase 实时数据库中删除一些数据，但出现此错误：Uncaught TypeError: ref2.orderByChild is not a function

这是代码：

import { initializeApp } from "https://www.gstatic.com/firebasejs/9.8.1/firebase-app.js";
import {getDatabase, ref, child, onValue, get} from "https://www.gstatic.com/firebasejs/9.8.1/firebase-database.js"
import "https://cdn.jsdelivr.net/npm/seamless-scroll-polyfill@latest/lib/bundle.min.js";
const firebaseConfig = {
  apiKey: "xxxxx",
  authDomain: "xxxxx",
  databaseURL: "xxxxx",
  projectId: "xxxxx",
  storageBucket: "xxxxx",
  messagingSenderId: "xxxxx",
  appId: "xxxxx"
};
const app = initializeApp(firebaseConfig);
const db = getDatabase();

var ref2 = ref(db, "/2021-2022/Pentamestre/Voti/Novità");
var now = Date.now();
var cutoff = now - 2 * 60 * 60 * 1000;
var old = ref2.orderByChild('timestamp').endAt(cutoff).limitToLast(1);
var listener = old.on('child_added', function(snapshot) {
  snapshot.ref.remove();
});

显然在 firebaseConfig 中存在数据，我只是将它们隐藏在这里

Answer 1

新的模块化 SDK 中有一个顶级函数 query() 可用于构建查询。同样，orderByChild()等查询约束也是一个函数。尝试重构代码，如下所示：

var old = query(ref2, orderByChild('timestamp'), endAt(cutoff), limitToLast(1));

var listener = onChildAdded(old, function(snapshot) {
    // ...
});

Answer 2

我看到你导入了“get”但没有使用它，并且参考“/2021-2022/Pentamestre/Voti/Novità”可能是

"2021-2022/Pentamestre/Voti/Novità"

因为路径不是以 /slash 开头

ref2.orderByChild 不是函数

ref2.orderByChild is not a function

javascript

firebase

firebase-realtime-database