如何在nodejs mongoose中将该回调认证转换为Promise

const mongoose = require('mongoose');

// 连接数据库
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

// 定义模型
const UserSchema = new mongoose.Schema({
  username: String,
  password: String
});
const User = mongoose.model('User', UserSchema);

// 使用Promise封装认证函数
function authenticate(username, password) {
  return new Promise((resolve, reject) => {
    User.findOne({ username, password }, (err, user) => {
      if (err) {
        reject(err);
      } else {
        resolve(user);
      }
    });
  });
}

// 调用认证函数
authenticate('admin', 'password')
  .then(user => {
    console.log('认证成功', user);
  })
  .catch(err => {
    console.error('认证失败', err);
  });