猫鼬“断开不是一种功能”

Question

我使用本教程来创建一个节点/mongo应用程序。当我运行addContact时，似乎联系人保存到DB中，但是，我看到一个错误，即断开连接函数不是函数。有谁能告诉我为什么会发生这种事，以及如何解决？我假设常量db的作用域有问题

代码：

const mongoose = require('mongoose'); 
const assert = require('assert'); 
mongoose.Promise = global.Promise; 


const db = mongoose.connect('mongodb://localhost:27017/contact-manager');


function toLower(v) {
  return v.toLowerCase();
}

const contactSchema = mongoose.Schema({
  firstname: { type: String, set: toLower },
  lastname: { type: String, set: toLower },
  phone: { type: String, set: toLower },
  email: { type: String, set: toLower }
});


const Contact = mongoose.model('Contact', contactSchema);

const addContact = (contact) => {
  Contact.create(contact, (err) => {
    assert.equal(null, err);
    console.info('New contact added');
    db.disconnect();
  });
};

const getContact = (name) => {
  const search = new RegExp(name, 'i');
  Contact.find({$or: [{firstname: search }, {lastname: search }]})
  .exec((err, contact) => {
    assert.equal(null, err);
    console.info(contact);
    console.info(`${contact.length} matches`);
    db.disconnect();
  });
};

module.exports = {  addContact, getContact };

代码part2：

const program = require('commander');

const {addContact, getContact} = require('./logic');

program
  .version('0.0.1')
  .description('Contact management system');

program
  .command('addContact <firstame> <lastname> <phone> <email>')
  .alias('a')
  .description('Add a contact')
  .action((firstname, lastname, phone, email) => {
    addContact({firstname, lastname, phone, email});
  });

program
  .command('getContact <name>')
  .alias('r')
  .description('Get contact')
  .action(name => getContact(name));

program.parse(process.argv);

错误：

New contact added
/Users/user/contact-manager/node_modules/mongodb/lib/utils.js:132
      throw err;
      ^

TypeError: db.disconnect is not a function
    at Contact.create (/Users/user/contact-manager/logic.js:33:8)
    at Function.<anonymous> (/Users/user/contact-manager/node_modules/mongoose/lib/model.js:3913:16)
    at parallel (/Users/user/contact-manager/node_modules/mongoose/lib/model.js:2077:12)
    at /Users/user/contact-manager/node_modules/async/internal/parallel.js:35:9
    at /Users/user/contact-manager/node_modules/async/internal/once.js:12:16
    at iteratorCallback (/Users/user/contact-manager/node_modules/async/eachOf.js:52:13)
    at /Users/user/contact-manager/node_modules/async/internal/onlyOnce.js:12:16
    at /Users/user/contact-manager/node_modules/async/internal/parallel.js:32:13
    at apply (/Users/user/contact-manager/node_modules/lodash/_apply.js:15:25)
    at /Users/user/contact-manager/node_modules/lodash/_overRest.js:32:12
    at callbackWrapper (/Users/user/contact-manager/node_modules/mongoose/lib/model.js:2046:11)
    at /Users/user/contact-manager/node_modules/mongoose/lib/model.js:3913:16
    at model.$__save.error (/Users/user/contact-manager/node_modules/mongoose/lib/model.js:342:7)
    at /Users/user/contact-manager/node_modules/kareem/index.js:297:21
    at next (/Users/user/contact-manager/node_modules/kareem/index.js:209:27)
    at Kareem.execPost (/Users/user/contact-manager/node_modules/kareem/index.js:217:3)

Answer 1

据我所知，mongoose.connect不会返回一个值，从入门指南中给出的代码可以看出这一点。如果要关闭数据库连接，则需要调用mongoose.connection上的mongoose.connection方法，该方法在使用mongoose.connect打开连接时被写入。最简单的方法是将mongoose.connect移动到自己的行：

mongoose.connect('mongodb://localhost:27017/contact-manager');
const db = mongoose.connection;

然后将对db.disconnect()的调用替换为对db.close()的调用。

Answer 2

尝试让猫鼬使用mongoose.connection.close()处理连接闭包