mongoose:与findOne一起返回的ObjectId未定义

const mongoose = require('mongoose');

// 连接到MongoDB数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('Connected to MongoDB');
  })
  .catch((error) => {
    console.error('Failed to connect to MongoDB', error);
  });

// 定义数据模型
const userSchema = new mongoose.Schema({
  name: String,
  age: Number
});

const User = mongoose.model('User', userSchema);

// 查询满足条件的第一条文档
User.findOne({ name: 'John' })
  .then((user) => {
    if (user) {
      console.log(user);
    } else {
      console.log('No matching document found');
    }
  })
  .catch((error) => {
    console.error('Failed to find document', error);
  });