如何在Mongoose中使用populate查询值？

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  name: String,
  age: Number
});

const articleSchema = new mongoose.Schema({
  title: String,
  content: String,
  author: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User' // 引用User模型
  }
});

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

Article.find().populate('author').exec((err, articles) => {
  if (err) {
    console.error(err);
    return;
  }
  
  console.log(articles);
});

Article.find({ title: /Node.js/ }).populate('author').exec((err, articles) => {
  if (err) {
    console.error(err);
    return;
  }
  
  console.log(articles);
});