Error while working with MongoDB?

Question

MongoDB

Hello!
MongoDB version 3.0.7
I just started learning MongoDB and immediately ran into a problem.
There is this simple code:

var MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://localhost:27017/mongotest',
  function(err, db) {
    console.log('Connected to MongoDB!');
    // using the db connection object, save the collection 'testing' to
    // a separate variable:
    var collection = db.collection('testing');
    // isert a new item using the collection's insert function:
    collection.insert({
      'title': 'Snowcrash'
    }, function(err, docs) {
      console.log(docs.length + ' record inserted.');
      console.log(docs[0].title + ' – ' + docs[0]._id);
      
      db.close();
    });
  });

And there is such an error

Help me understand what kind of error it is, and how to fix it, if not difficult.

Answer 1

1. The console prints "undefined record inserted".
   
2. So docs.length is undefined.
   
3. So the insert failed.
   
4. So, you need to look at the contents of the error, which is passed as the first parameter to the function for precisely these purposes.