Get _id of an newly inserted Item

[Sebastian Sommer]

Hey, I'm not able to get out the _id after I insert a new item to my meteor-db.
My code looks like this:
Server:

newItem() {
   if (!this.userId)
     throw new Meteor.Error('unauthorized', 'User must be logged-in to insert an item');

   return Items.insert({ ownerId: this.userId, title: 'New Item' });
}

Client:

MeteorObservable.call('newItem').subscribe({

  next: () => {
    //get _id 
  },
  error: (e: Error) => {
    console.log("Error: " + e);
  }

});

Can you please tell me how to get the _id?
I also posted here: http://stackoverflow.com/questions/41040730/ionic2-meteor-get-id-of-new-inserted-item

[Sebastian Sommer]

Ok, error was on the server-side. Items.collection.insert(...) is correct. So not a problem of MeteorObservable, sorry.