'query' does not exist in type 'QueryFn' | angularfire2

Question

Argument of type \'{ query: { limitTolast: number; orderByKey: boolean; }; }\' is not assignable to parameter of type \'QueryFn\'.Object literal may only specify known propertie

Answer 1

QueryFn must return a firebase.database.Query, not void. You can code the query like this one, for more clear:

getMessages(): Observable {
    return this.db.list('/messages', ref => {
      let q = ref.limitTolast(25).orderByKey(true);
      return q;
    });
  }