Socket.io integration for message broadcasting

Here is the code that will perform the RethinkDB changefeed operation and event broadcasting:

var rethinkdb = require('rethinkdb'); 
var db = require('./db'); 
var pollObject = new db(); 
module.exports = function(socket) { 
  pollObject.connectToDb(function(err,connection) { 
  if(err) { 
    return callback(true,"Error connecting to database"); 
  } 
  // Look over this line carefully. 
  // we are invoking changes() function on poll table. 
  // On every change it will give us data. 
  rethinkdb.table('poll').changes().run(connection,function(err,cursor) { 
    if(err) { 
      console.log(err); 
    } 
    // We are scrolling over the cursor data and broadcasting the changes using socket. 
    cursor.each(function(err,row) { 
      console.log(JSON.stringify(row)); 
      if(Object.keys(row).length > 0) { 
        socket.broadcast.emit("changeFeed...