'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

You can try this code:

return this.db.list('/categories', ref => ref.orderByChild('name')).valueChanges();

Answer 2

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

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

Answer 3

due to update on Angular Fire, replace FirebaseListObservable to AngularFireList and make sure you return firebase.database.Query like this

 getMessages(): AngularFireList<ChatMessage[]> {
    return this.db.list('messages', ref => {
      return ref.limitToLast(25).orderByKey();
    });
  }

Answer 4

It's not working, because AngularFire expects a function to be passed as a second argument.

I think your example was the right way to go during the beta version. (not 100% sure)

You have use it the following way:

// make sure to provide a child in the orderByChild call
getMessages(): Observable<ChatMessage[]> {
    return this.db.list('/messages', ref => {
      return ref.limitTolast(25).orderByKey(true)
    });
  }

Learn more about querying lists here: https://github.com/angular/angularfire2/blob/master/docs/rtdb/querying-lists.md

Answer 5

This will work perfectly. Tried by me

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

for more information related to queries goto this link: https://github.com/angular/angularfire2/blob/master/docs/rtdb/querying-lists.md