如何查找子文档值相等的Mongoose文档

const mongoose = require('mongoose');

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

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

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

Parent.find({ children: { $elemMatch: { value: '相等的值' } } }, (err, docs) => {
  if (err) {
    console.error(err);
  } else {
    console.log(docs);
  }
});

Parent.findOne({ children: { $elemMatch: { value: '相等的值' } } }, (err, doc) => {
  if (err) {
    console.error(err);
  } else {
    console.log(doc);
  }
});