MongoError: Econnrefused

I am just learning MongoDB and Node.js. I am doing this very simple exercise from the video in which I am trying to connect my Node.js app to my MongoDB and I am getting this error:

{[MongoError: connect ECONNREFUSED] name: "MongoError", message: "connect ECONNREFUSED"}

First of all, I set up a database on mongo and tested some commands in the terminal:

$mongod (everything ok)
$mongo (everything ok)

      

        
        
        
      

    

.. and then I created a database called "products" and added some products to it. When I hit:

db.products.find()

      

        
        
        
      

    

It returns:

{
"_id": ObjectId("55b2b27d7f9f84490b8a9170"),
  "name": "beer",
  "description": "belgian craft beer",
  "price": 20
}
{
  "_id": ObjectId("55b2b2c27f9f84490b8a9171"),
  "name": "whisky",
  "description": "scotch blended 18 years old",
  "price": 150
}
{
  "_id": ObjectId("55b2b3e47f9f84490b8a9172"),
  "name": "cachaça",
  "description": "typical brazilian cachaça",
  "price": 10
}
{
  "_id": ObjectId("55b2b4087f9f84490b8a9173"),
  "name": "water",
  "description": "water from the swiss alps",
  "price": 5
}
{
  "_id": ObjectId("55b2b2617f9f84490b8a916f"),
  "name": "wine",
  "description": "red porto wine",
  "price": 80,
  "tags": [
    "porto",
    "sweet",
    "wine"
  ]
}

      

        
        
        
      

    

My app.js:

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/products');

var db = mongoose.connection;

db.on('error', function(err){
    console.log('Erro de conexao.', err)
});
db.on('open', function () {
    console.log('Conexão estabelecida.')
});
db.on('disconnected', function(err){
    console.log('Desconectado')
});

      

        
        
        
      

    

And my package .json:

{
  "name": "aula-mongoose",
  "version": "0.0.1",
  "description": "aula sobre mongoose",
  "main": "app.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [
    "node.js",
    "mongodb"
  ],
  "author": "Guga",
  "license": "WTFPL",
  "dependencies": {
    "mongoose": "^4.1.0"
  }
}

      

        
        
        
      

    

I read many posts about this, even the threads here. But I could not figure out what was wrong here.

EDIT:

By accident I tried to connect to $ mongod while it was already running and I was prompted with this error:

errno: 48 Address already in use for socket: 0.0.0.0:27017

So, I changed this line in my app.js to:

mongoose.connect('mongodb://0.0.0.0:27017/products');

      

        
        
        
      

    

And it worked. But I have no idea why. Anyone?