title: Property filter is not available for type Observable<any> despite importing
body: <p>I want to filter a list of names which I get from an API. I want to do so with the filter operator. But I get this error: </p>
  
  <pre><code>&gt; Property filter is not available for type Observable&lt;any&gt;
  </code></pre>
  
  <p>despite importing</p>
  
  <pre><code>import { map, filter } from 'rxjs/operators';
  </code></pre>
  
  <p>I took this tutorial of Josh Morony as an orientation: <a href="https://www.joshmorony.com/high-performance-list-filtering-in-ionic-2/" rel="nofollow noreferrer">https://www.joshmorony.com/high-performance-list-filtering-in-ionic-2/</a></p>
  
  <p>My Code:</p>
  
  <p>service.ts</p>
  
  <pre><code>  getList(): Observable&lt;any&gt; {
          return this.http.get(this.url);
        }
  </code></pre>
  
  <p>page.ts</p>
  
  <pre><code> public searchTerm: string = "";
   userList: Observable&lt;any&gt;;
  
  ngOnInit() {
  
      this.getAllUsers();
  }
  
  
    getAllUsers() {
      this.userList = this.userService.getList()
      .pipe(map(response =&gt; response.results));
    }
  
  
  filterUsers (searchTerm) {
    return this.userList.filter (user =&gt; {
      return user.username.toLowerCase().indexOf(searchTerm.toLowerCase()) &gt; -1;
      });
  }
  
  SearchList() {
    this.userList = this.filterUsers (this.searchTerm);
  }
  </code></pre>
  
  <p>page.html</p>
  
  <pre><code>&lt;ion-searchbar mode="ios" class="items-searchbar" animated mode="ios" [(ngModel)]="searchTerm" (ionChange)="searchList()" placeholder="Filter by name..."&gt;&lt;/ion-searchbar&gt;
  </code></pre>