Property 'filter' does not exist in type 'FirebaseListObservable'

Question

I use Ionic 2 and Firebase to create a chat application.

I am adding the following, which should be used to add a filter:

import 'rxjs/add/operator/filter';
        ...
public af: AngularFire
        ...
    this.firelist = this.af.database.list('/chat/', {
      query: {
        orderByChild: 'negativtimestamp'
      }
    }).filter(item => item.memberIds === 'xxx');

However, I get the following:

[ts] The property 'filter' does not exist for type 'FirebaseListObservable'.

ps. this.af.database.list(...)returns a FirebaseListObservable<any[]>. filtercan do on Observable, but not on FirebaseListObservable.

Question

So, how do I implement filteron FirebaseListObservablebecause class FirebaseListObservable<T> extends Observable<T>?

AND

import 'rxjs/add/operator/map'
            ...
    this.af.database.list('').map(item => {});

has the following error:

[ts] The property 'map' does not exist in the type 'FirebaseListObservable'.

Additional Information:

My package.jsonhas:

 "rxjs": "5.0.0-beta.12",

Any help was appreciated.

UPDATE

YouTube, , , . - , ? "angularfire2": "^2.0.0-beta.7-pre",.

Answer 1

​​ :

"angularfire2": "^2.0.0-beta.7.1-pre",

:

npm install firebase angularfire2@^2.0.0-beta.7.1-pre --save