带有express的节点js不加载mongodb数据库内容

const express = require('express');
const MongoClient = require('mongodb').MongoClient;

const app = express();
const port = 3000;

// MongoDB连接信息
const url = 'mongodb://localhost:27017';
const dbName = 'mydatabase';

// 连接MongoDB数据库
MongoClient.connect(url, { useNewUrlParser: true }, (err, client) => {
  if (err) {
    console.error('Failed to connect to MongoDB:', err);
    return;
  }

  console.log('Connected to MongoDB successfully');

  const db = client.db(dbName);

  // 查询数据库中的数据
  db.collection('mycollection').find({}).toArray((err, result) => {
    if (err) {
      console.error('Failed to fetch data from MongoDB:', err);
      return;
    }

    console.log('Fetched data from MongoDB:', result);

    // 在路由中传递数据给前端页面
    app.get('/', (req, res) => {
      res.send(result);
    });
  });
});

// 启动服务器
app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});