The Notifications module aims to register all the application events a user might be interested. At a database level, those events are stored in the notifications collection. On the frontend, they are displayed in the /notifications page, accessible through the bell icon near the user badge.

Until now, we are registering three kind of events:

The model

In lib/models/notification.js is declared the NotificationSchema that defines the Notification Mongoose model. It has the following properties:

There is a virtual method, url, that returns the URL of the target object (in this case, the topic that holds the replied/upvoted/downvoted comment).

API endpoints

Notifications are created and pushed to the database via an internal API. They cannot be created through the public API, but they can be queried. The public API is located in lib/notification-api/index.js and has only one endpoint: GET /api/notification/all, that delivers all the notifications for the logged in user (the app forbids to retrieve notifications of other user).

Pushing a new notification

Internally, the notifications are pushed to the notifications collection through the lib/notifications/index.js module, by calling the send function. That function overrides the NotifierClient#send() function, that internally calls two asynchronous functions: one pushes the notification document and the other one calls notifier to send a notification e-mail.

Notification page

The notifications page is accessible by browsing to /notifications or clicking in the bell icon next to the user badge. The page lifecycle is handled in the lib/notifications-page module.

What about notifier?

The notifications module does not replace the notifier module. They work together and its responsibilities are different: notifications responsibility is to push a notification document into the notifications collection on the database. notifier‘s responsibility is to send an e-mail using the configured transport.


We are heading to change notifier behavior by making it poll the notification collection in order to find unread notifications and build and send a digest e-mail notifying all together the pending events of a user.

Also, we are continuously improving the notifications module to make it more usable.