Mongoose -如何找到并列出链接到另一个集合的集合？

const mongoose = require('mongoose');

const UserSchema = new mongoose.Schema({
  name: String,
  posts: [
    {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'Post' // 链接到Post集合
    }
  ]
});

const PostSchema = new mongoose.Schema({
  title: String,
  content: String
});

const User = mongoose.model('User', UserSchema);
const Post = mongoose.model('Post', PostSchema);

User.findOne({ name: 'John' })
  .populate('posts') // 将posts字段替换为实际的文章对象
  .exec(function (err, user) {
    if (err) {
      console.log(err);
    } else {
      console.log(user.posts);
    }
  });