Get _id after insert from returned Observable on client

Hey, I’m in an Ionic2/Angular2 project and I’m using a meteor-server and it’s working quite fine. But now I would need the newly generated _id for my last inserted item to forward my app to the new item’s page after the insert.

On the server I’m doing an insert inside its method-calls:

Meteor.methods({
   newSpot() {
      return Spots.insert({ ownerId: this.userId, title: 'New Spot' });
   }
...

I call this on my client like this (got this lines from the tutorial):

newSpot() {
    MeteorObservable.call('newSpot').subscribe({
      next: () => {
        //get _id here
      },
      error: (e: Error) => {
        console.log("Error: " + e);
      }
    });
  }

I found lot of answers to the same question, but it looks like that older versions returns just the _id-string on the insert, but now it returns an Observable and all answers refer to the old versions.

On the server I’m able to get the _id out of the Observable, so I’ve tried to only return the _id-string, but this also didn’t work. I’m not able to get out any data on the client side.

If there is any other way I should do the call on the client or if the call is fine to get the _id with it, please let me know how. Thank you so much!

Edit: I also posted it here: http://stackoverflow.com/questions/41040730/ionic2-meteor-get-id-of-new-inserted-item

Error was on server-side. Had to do it with Spots.collection.insert(…);
Can someone tell me why?