javascript - Mongoose "disconnect is not a function"

Question

我正在使用 this tutorial制作 Node/mongo 应用程序。当我运行 addContact 时，联系人似乎已保存到数据库中，但我收到一条错误消息，指出断开连接功能不是一个功能。谁能告诉我为什么会这样，以及如何解决？我假设常量 db 的范围存在一些问题？

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 };

代码第二部分:

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

mongoose.connect 没有返回值，据我看 getting started guide 中给出的代码可以看出.如果你想关闭数据库连接，你需要调用 mongoose.connection 上的 close 方法，当你用 mongoose.connect 打开连接时写入该方法。最简单的方法是将 mongoose.connect 移动到它自己的行:

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

然后只需将对 db.disconnect() 的调用替换为对 db.close() 的调用即可。