I've been trying to set up a basic MongoDB example on my puter. But I can't get much to work.

When I try to retrieve a collection from my DB (there is only one), I get the error:

TypeError: db.getCollection is not a function

If I try accessing my collection directly by it's name, I get the error

TypeError: Cannot read property 'insert' of undefined

I created my database online on mLab, so I know the collection exists.

This is my server.js:

const express        = require('express');
const MongoClient    = require('mongodb').MongoClient;
const bodyParser     = require('body-parser');
const app            = express();
const db             = require('./db');
const port = 8000;

app.use(bodyParser.urlencoded({ extended: true }));

MongoClient.connect(db.url, (err, database) => {
  if (err) return console.log(err)
  require('./app/routes')(app, database);
  app.listen(port, () => {
    console.log('We are live on ' + port );
  });               
})

And this is my route:

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

Why can't I access the getCollection() function?

I've been trying to set up a basic MongoDB example on my puter. But I can't get much to work.

When I try to retrieve a collection from my DB (there is only one), I get the error:

TypeError: db.getCollection is not a function

If I try accessing my collection directly by it's name, I get the error

TypeError: Cannot read property 'insert' of undefined

I created my database online on mLab, so I know the collection exists.

This is my server.js:

const express        = require('express');
const MongoClient    = require('mongodb').MongoClient;
const bodyParser     = require('body-parser');
const app            = express();
const db             = require('./db');
const port = 8000;

app.use(bodyParser.urlencoded({ extended: true }));

MongoClient.connect(db.url, (err, database) => {
  if (err) return console.log(err)
  require('./app/routes')(app, database);
  app.listen(port, () => {
    console.log('We are live on ' + port );
  });               
})

And this is my route:

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

Why can't I access the getCollection() function?

• javascript
• mongodb

• stackoverflow./questions/47658775/… – wrangler Commented Dec 9, 2017 at 19:16
• Thanks, I tried that, I got the same error. – apat Commented Dec 9, 2017 at 20:51

1 Answer 1

Because in the mongodb js library (proper name is node-mongodb-native) .getCollection() does not exist as a method on the db object.

Instead call db.collection() (or one of the other similar methods).

collection(name, options, callback){Collection}

Fetch a specific collection (containing the actual collection information). If the application does not use strict mode you can use it without a callback in the following way: const collection = db.collection('mycollection');