Offline sync Ionic2 app to mongodb backend

I am building a mobile app with Ionic2.
The backend service is MongoDb.

The data is generated on the mobile app (GPS paths). User can also upload
the tracks via a browser.
The goal is to keep a list of all GPS recordings on the mobile in sync with backend.

I could use for storing data on mobile PouchDb, ForerunnerDb, sqllite or localstorage.
The question is what is the technique to sync data with the backend?
PouchDb requires CouchDb on the server, so not an option.
I could write some sync code myself, but would not want to re-invent the wheel if it’s possible.

Could you pls share how you do it? I don’t really care about deletion of items and updates,
once a track was created.

When you want to keep it “sync” then you DO CARE about “deletion of items and updates,”.

Either you go with Pouch and Couch or you implement your own revision strategy and connect your MongoDB to a API.

I meant, there is no functionality in the app to remove items and edit them,
that why I don’t care. This can make the sync algo simpler.

I wonder what those who have MongoDb in the backend do?