archeive.js

var express = require('express');
var http = require('http')
var mongojs = require('mongojs');
var ObjectID = mongojs.ObjectID;
var db = mongojs(process.env.MONGO_URL || 'mongodb://localhost:27017/local');
var archeive = mongojs(process.env.MONGO_URL || 'mongodb://localhost:27017/admin');
var app = express();
var server = http.Server(app);
const chatLimit = 5;
server.listen(3004, () => console.log('listening on *:3004'));


db.collection('messages').aggregate(
    [{
        $group: {
            _id: '$chatId'

        }
    }]
).toArray(function(err, data) {
    data.forEach(function(item) {
        db.collection('messages').find({
            chatId: item._id
        }, function(err, messages) {
            if (err) return res.status(500).send('Internal Server Error');
            var chatCount = messages.length;
            if (chatCount > chatLimit) {
                db.collection('messages').find({
                    chatId: item._id
                }).limit(5, function(err, rdata) {
                    rdata.forEach(function(rdataO) {
                        archeive.collection('messages').insert(rdataO, function() {
                            db.collection('messages').remove(rdataO);
                        });
                    })
                });
            }
        });
    })
});