I am trying to implement Effects for my ngrx state manager. Currently I am using `Angular v5.2.1`, `ngrx v4.1.1` and `rxjs v5.5.6`. 
I tried "older" proach for example

```
@Effect() login$: Observable<Action> = this.actions$.ofType('LOGIN')
.mergeMap(action =>
  this.http.post('/auth', action.payload)
    // If successful, dispatch success action with result
    .map(data => ({ type: 'LOGIN_SUCCESS', payload: data }))
    // If request fails, dispatch failed action
    .catch(() => of({ type: 'LOGIN_FAILED' }))
);

```

But I was getting an error `Property 'mergeMap' does not exist on type 'Actions<Action>'`. 
So I used new `pipe` method. The problem is when I try to import `ofType` operator

```
// ...
import { Action } from '@ngrx/store';
import { Effect, Actions, ofType } from '@ngrx/effects';

import { map, mergeMap, catchError } from 'rxjs/operators';
import { of } from 'rxjs/observable/of';

@Injectable()
export class WifiEffects {

  @Effect()
  getWifiData: Observable<Action> = this.actions$.pipe(
    ofType(WifiTypes.getWifiNetworks),
    mergeMap((action: GetWifiNetworks) =>
      this.mapService.getWifiNetworks().pipe(
        map((data: WifiNetworks) => new GetWifiNetworksSucc(data)),
        catchError(() => of(new GetWifiNetworksErr()))
      )),
  );

  constructor (
    private actions$: Actions,
    private mapService: GoogleMapDataService
  ) {}

}

```

Iam getting an error `Module '".../node_modules/@ngrx/effects/effects"' has no exported member 'ofType'.` Any ideas?