Node js＆mongoDB - TypeError：db.collection不是函数

Question

我想从POSTMAN发布数据到我在mLab上创建的外部数据库，但我得到错误db.collection不是函数。

有一个类似的问题线程，但答案是不完整的，并不保存我把邮递员放入mLab的任何键/值。我试图使工作的代码是从本教程：https://medium.freecodecamp.com/building-a-simple-node-js-api-in-under-30-minutes-a07ea9e390d2

我的代码：

Server.js

const express = require('express'); // Load routes application 
const MongoClient = require('mongodb').MongoClient; //Load database connection application 
const db = require('./config/db'); 
const app = express(); // Assign express app a variable 
const port = 8000; //Set local port value for server 
const bodyParser = require('body-parser'); // **This has to come BEFORE routes 
var assert = require('assert'); // ? 
var databaseURL ='mongodb://external:api@ds123312.mlab.com:23312/soundfactory'; 


app.listen(port,() => { 
    console.log('') 
    console.log('We are live on ' + port); 
    console.log('') 
}); 


MongoClient.connect(databaseURL, function(err, db) { 
    assert.equal(null, err); 
    console.log("API has succesfully connected to Sound Facotry mlab external database."); 
    console.log('') 
    db.close(); 
}); 


app.use(bodyParser.urlencoded({ extended: true })) 
require('./app/routes')(app, {}); //Must come AFTER express w/ body parser 

db.js

module.exports = { 
    url : 'mongodb://external:api@ds123312.mlab.com:23312/soundfactory' 
}; 

指数。 js

const noteroutes = require('./note_routes'); 
module.exports = function(app,db) 
{ 
    noteroutes(app,db); 
}; 

个

note_routes.js

module.exports = function(app, db) { 
    app.post('/notes', (req, res) => { 
    const note = { text: req.body.body, title: req.body.title }; 
    db.collection('notes').insert(note, (err, result) => { 
     if (err) { 
     res.send({ 'error': 'An error has occurred' }); 
     } else { 
     res.send(result.ops[0]); 
     } 
    }); 
    }); 
}; 

部分正确的代码

server.js（代码部分作品&不抛出db.collections错误，如我原来的server.js文件）

const express = require('express'); 
const MongoClient = require('mongodb').MongoClient; 
const bodyParser = require('body-parser'); 
const db = require('./config/db'); 
const app = express(); 
const port = 8000; 
app.use(bodyParser.urlencoded({extened:true})); 
MongoClient.connect(db.url,(err,database) =>{ 
if (err) return console.log(err) 
//require('./app/routes')(app,{}); 
//check below line changed 
require('./app/routes')(app, database); 
app.listen(port,() => { 
    console.log("We are live on"+port); 
}); 
}) 

Answer 1

更改为此require('mongodb').MongoClient;

Answer 2

取出node_modules文件夹，并改变你的package.json

"mongodb": "^2.2.33" 

MongoDB的版本，下面的代码运行：

npm install