如何使用另一个模型进行mongoose查询以获得最近注册的位置？

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  username: String,
  registrationDate: Date,
  location: String
});

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

const locationSchema = new mongoose.Schema({
  userId: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User'
  },
  latitude: Number,
  longitude: Number,
  timestamp: Date
});

const Location = mongoose.model('Location', locationSchema);

Location.findOne()
  .sort({ timestamp: -1 })
  .populate('userId')
  .exec((err, location) => {
    if (err) {
      console.error(err);
      return;
    }

    console.log('最近注册的位置：', location);
    console.log('位置对应的用户：', location.userId);
  });