带有异步等待的Mongoose查询

const mongoose = require('mongoose');

// 连接数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    console.log('数据库连接成功');
  })
  .catch((error) => {
    console.error('数据库连接失败', error);
  });

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

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

// 异步等待的Mongoose查询
async function getUserById(userId) {
  try {
    const user = await User.findById(userId);
    return user;
  } catch (error) {
    console.error('查询用户失败', error);
    return null;
  }
}

// 使用异步等待的Mongoose查询
getUserById('1234567890')
  .then((user) => {
    if (user) {
      console.log('查询到用户', user);
    } else {
      console.log('未找到用户');
    }
  });