How to obtain success message from conditional upsert using Dgraph JS gRPC client?

Users
3

Here is my query:

upsert{
query {
    tree as var( func: uid(0xabc11) )
    {
      defects:~parent_tree @filter(type(Defect))
      {
          d as uid
      }              
    }

    var(func: uid($uid))
    {
      child_tree: ~parent_tree @filter(type(Tree))
      {
          ct as uid
      }              
    }
  }

mutate @if( eq( len(d), 0) AND eq( len(ct), 0) ){
     delete {
         uid(tree) * *.
     }
}
}

I like to get a confirmation message that the tree is delete from the client. However I am not able to do so. For example, when it fails the conditions and do not delete, the message i receive is still “success”.