getting data from mongodb collection - mongodb

Question

Trying to get some messages from a db collection, I've tried that code (server side):
MongoClient.connect('mongodb://127.0.0.1:27017/gt-chat', function(err, db) {
if(err) throw err;
var history="";
var collection = db.collection('gt-chat');
console.log("******************************Printing docs from Cursor Each")
collection.find({}, {_id: 0}).sort({$natural: 1}).limit(20).each(function(err, doc) {
console.log(doc)
if(doc != null) {
console.log("Doc from Each ");
history=history+console.dir(doc)+"\r\n";
console.dir(doc);
}
});
console.log("/////////////HISTORY//////////////////");
console.log(history); ; // data is shown there under the shell console, all is fine !
socket.emit('updatechat', 'SERVER', history); // should send the messages using socket
});
and then on the client side, I've tried :
// listener, whenever the server emits 'updatechat', this updates the chat body
socket.on('updatechat', function (username, data) {
date = new Date;
h = date.getHours();
if (h<10) {
h = "0"+h;
}
m = date.getMinutes();
if (m<10) {
m = "0"+m;
}
s = date.getSeconds();
if (s<10) {
s = "0"+s;
}
var time = h+":"+m+":"+s;
$('#conversation').append('<b><strong>' + time + '</strong> '+username + ':</b> ' + data + '<br>');
});
which doesn't show anything as expected :(
I am quite sure about the updatechat function because I can get message with it, as I've tried:
socket.emit('updatechat', 'SERVER',"this is history"); // < message is well sent, so no problem there!
but I don't get the all history.
So the goal is to get some messages from a mongodb collection and to display them under the browser using socket emit
Under the shell, to debug, it's showing:
Doc from Each { message: '<strong>12:16:27</strong><span style=\'color:#2fed7e\'><b>guibs</b>< /span><em> hum</em>' } { message: '<strong>12:16:27</strong><span style=\'color:#2fed7e\'><b>guibs</b>< /span><em> hum</em>' }
So, data and messages exist, but I can't read them from the browser. The shell says: 'history is not defined' ! What is wrong with concatenation? And my variable declaration? I don't understand, thanks for your help!