before fetching data in db response is sent by node js - node.js

Question

this is my set notification object
var sentNotificationObj = function (notification, eventid, addedorganizerpropic) {
this.notification = notification;
this.eventid = eventid;
this.addedorganizerpropic = addedorganizerpropic;
}
this is my array which is stored notification obect
var notificationSetArray2 = [];
this is my api of getnotification
router.post('/getnotification', function (req, res) {
console.log('in aside');
var id = req.body.userid;
console.log('pos id' + id);
User.findById({ _id: id }, function (err, result) {
if (err) {
console.log('err get notification');
res.statusCode = 500;
res.json({
success: false,
message: "severe error"
});
} else {
this is code fetchin data in data base
for (var i = 0; i < result.notification.length; i++) {
var addedevent = result.notification[i].addedevent;
var notification = result.notification[i].notification;
console.log('added event' + addedevent);
console.log('added noti' + notification);
User.findById({ _id: result.notification[i].addedorganizer }, function (err, addedorganizer) {
if (err) {
console.log('error get added user pofile pic');
} else {
convert image to base64
var base64str = base64_encode(addedorganizer.profileData.profileurl);
console.log(base64str);
console.log(notification);
console.log(addedevent);
var newsentNotificationObj = new sentNotificationObj(notification, addedevent, base64str);
notificationSetArray2.push(newsentNotificationObj);
console.log('succe get added user profile pic');
}
});
}
this is response
res.statusCode = 200;
res.json({
success: true,
notificationArray: notificationSetArray2
})
console.log(notificationSetArray2);
notificationSetArray2.length = 0;
}
});
});

Answer 1

The most simple solution in here to use async library here.
Node runs code in asynchronous way. So it is natural to send response before fetching any data from your database.
By using async you can execute this in a sequence. So it will be solved.
Use async.series method for solve this. For example
async.series(
[
function(callback){
// fetch your data here using mongo with your loop
//
//
callback(); // this will trigger next step (call this after you finished iterating array)
},
function(callback){
// after above code has been executed
// send response here
callback() // call this to proceed
}
],
function(err){
// handle any error in here
}
)
A good example of how to use asyncjs in node