在Mongoose中填充包含ref的数组的数组

const mongoose = require('mongoose');

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

const parentSchema = new mongoose.Schema({
  children: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Child'
  }]
});

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

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

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

parent.save()
  .then(() => console.log('Parent saved'))
  .catch(error => console.error(error));

Parent.findOne({}).populate('children')
  .then(parent => console.log(parent))
  .catch(error => console.error(error));