Confusion between mongoose.connection() and mongoose.createConnection()

Question

I've been studying mongoose for three days and I'm a bit confused about the use of these two methods (i know that "mongoose.connection()" will be deprecated in the future...) The problem is: when I'm trying to convert (from "mongoose.connection()" to "mongoose.createConnection()") the action.js file of this example https://gist.github.com/2785463 it seems to not work for me... there's my code... ``` var mongoose = require('mongoose'), db = mongoose.createConnection('localhost', 'test'); db.on('error', function () { console.log('Error! Database connection failed.'); }); db.once('open', function (argument) { console.log('Database connection established!'); mongoose.connection.db.collectionNames(function (error, names) { if (error) { console.log('Error: '+ error); } else { console.log(names); }; }); }); ``` and there's my terminal output (typing "node test.js" on my ubuntu terminal..) ``` Database connection established! /home/_user_/Scrivania/node_modules/mongoose/node_modules/mongodb/l…

Accepted Answer

If you don't call `mongoose.connect()` then `mongoose.connection` doesn't contain an an open connection. You should be using the return value from your `mongo.createConnection()` call instead (that you've saved into `db`).

So the last section of code should change to:

UPDATED

```
db.db.collectionNames(function (error, names) {
  if (error) {
    console.log('Error: '+ error);
  } else {
    console.log(names);
  };
});
```

I don't see a `collectionNames` method on `Connection`; looks like you have to follow properties down into the native connection object to access that (see above code).

Confusion between mongoose.connection() and mongoose.createConnection()

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