如何在Mongoose中填充嵌套在对象数组中的文档？

const mongoose = require('mongoose');

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

const parentSchema = new mongoose.Schema({
  children: [childSchema]
});

const Parent = mongoose.model('Parent', parentSchema);

const child1 = new Child({ name: 'Child 1', age: 10 });
const child2 = new Child({ name: 'Child 2', age: 12 });

const parent = new Parent({ children: [child1, child2] });

parent.save();

Parent.findOne({})
  .populate('children')
  .exec((err, parent) => {
    if (err) {
      console.error(err);
    } else {
      console.log(parent);
    }
  });