在一个新的firebase.initializeApp之后（假设你使用的是firebase的v9），你需要以不同的方式示例化数据库。检查你的文档。我会这样写你的代码：

// firebase file which you export the initialization
import firebase from "firebase";


var firebaseConfig = {
  apiKey: "", // Add API Key
  databaseURL: "" // Add databaseURL
};

// Initialize Firebase
var fire = firebase.initializeApp(firebaseConfig);
export fire.

//second js file
import firebase from ./firebase.js
import {getDatabase, ref, set} from "firebase/database";

var db = getDatabase(Firebase);

export const userName = localStorage.getItem('auth_name');
const urlparams = new URLSearchParams(window.location.search);
const roomId = urlparams.get("id");

//if you want to push to the db or something, you call the method
set(ref(db, 'users/' + userId), {
    username: name,
    email: email,
    profile_picture : imageUrl
  });

//more code here

总而言之，再检查一次文档，使用版本9，它的实现是最好的。https://firebase.google.com/docs/database/web/read-and-write#web-version-9_1

这对我来说很好。

import { initializeApp } from "firebase/app";
import "firebase/compat/auth";
import "firebase/compat/firestore";
import { child, getDatabase, push, ref } from "firebase/database";

const firebaseConfig = {
    apiKey: "", // Add API Key
    databaseURL: "" // Add databaseURL
};

const app = initializeApp(firebaseConfig);
export const db = getDatabase(app);

var firepadRef = ref(db);

export const userName = prompt("What's your name?");
const urlparams = new URLSearchParams(window.location.search);
const roomId = urlparams.get("id");

if (roomId) {
    firepadRef = child(firepadRef, roomId);
} else {
    firepadRef = push(firepadRef);
    window.history.replaceState(null, "Meet", "?id=" + firepadRef.key);
}

export default firepadRef;