forEach执行后如何关闭mongoose连接？

 console.log('Mongoose connection is disconnected');

const mongoose = require('mongoose');
const connection = mongoose.connection;

// 建立数据库连接
mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true });

// 在forEach执行后关闭连接
myModel.find().forEach(function(doc) {
  // 处理每个文档
}).then(function() {
  // 关闭连接
  connection.close(function () {
    console.log('Mongoose connection is disconnected');
  });
});