Execute a module after making a POST request

I'm trying to integrate sending real-time information through sockets (using socket.io ), and sending push notifications using the OneSignal platform .

It happens that if I put everything in the same module, I don't know why the method to send the notification is not executed after the information is sent, or before sending the information.

If I execute the command npm start, no error appears, but the notification arrives as soon as the local or remote server is running, and in this way I do not want it to happen.

user.js

var express = require('express');
var router = express.Router();
var misocket = require('../routes/misocket');
var notificacion = require('../routes/notificacion');

/*

Si pongo esto asi, apenas envia el servidor, arranca de una vez y envia la notificacion
notificacion();

 */
/* GET users listing. sendnote*/
router.post('/sendasig', function (req, res, next) {

    console.log(misocket); //registrednote
    misocket.emit("registrar", req.body);
    //La idea es que se ejecute aqui, pero no logro hacer que esto suceda
    notificacion();
    console.log(req.body);

    res.status(200).json({
        message: "send message"
    });

});

module.exports = router;

notification.js

module.exports = function () {

    var OnesignalNotificationApi = require('onesignal-notification');
    var api = new OnesignalNotificationApi('N2FkY2ZkZWQtMGQ2MS00ZTUwLTlkM2QtODA2NmE0YjBiMzQ3',
            'c4b92cce-4d59-4550-a4be-20939370e39c');

    var message = {
        it: 'Some message',
        en: 'Some message',
        es: 'Nueva Calificacion'
    };

    api.sendToAll(message, null, function (err, res) {
        console.log(err);
        console.log(res);
    });

};

app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var misocket = require('./routes/misocket');
var index = require('./routes/index');
var users = require('./routes/users');
var io = require("socket.io");
var app = express();
app.io = io();

var Twitter = require('twitter');

var client = new Twitter({
  consumer_key: 'XXX',
  consumer_secret: 'XXX',
  access_token_key: 'XXX',
  access_token_secret: 'XXX'
});


// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', index);
//app.use('/api', users);
app.post("/sendnote",function(req,res,next){

  app.io.emit("registrednote",req.body);

  res.status(200).json({
                    message  : "send message"
                });
});
//copias y modificas la ruta del post
app.post('/sendasig', function(req, res, next) {

  app.io.emit("registrar",req.body);
  res.status(200).json({
                    message  : "send message"
                });

});

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});


misocket.connection(app.io);

module.exports = app;