I want to make sure that my previous function must be executed completely before the following code in Nodejs server side scripting

Question

I want to make sure that my previous function must be executed completely before the following code in Nodejs server side scripting

I wanted to make sure that my mongodb connected successfully in the function mongoConnect, before I start quering on it, because in NodeJS is non blocking and it keeps on going executing statements

I just wanted to know if there is some function like ".then(function(){..})" on the server side or anyother thing like that, i know there are callback functions which are used for the purpose but i dont know how to use it here, i mean in my case.

Heres my code:

io.sockets.on('connection', function (socket) {

mongoConnect();
//Some Query to the Database

socket.on('login',function(user)
{
        controller.loginUser(user);
 });
});

function mongoConnect()
  {
      var mongoose = require('mongoose');
       mongoose.connect('mongodb://xxxxxx-xxx-xxx.mongolab.com:xxx/xxxx');
  }

javascript
node.js
mongodb
callback

Answer 1

You can use mongoose.once to wait for the 'open' event and then, execute your callback.

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

var db = mongoose.connection;
db.once('open', function callback () {
   // Stuff here
});

Check this site for reference: http://mongoosejs.com/docs/index.html