Return observable from catch operator

catch.ts

// rxjs 5.4, ngrx 4.0.0, angular 4.0.0
import {Injectable} from '@angular/core';

@Injectable()
export class Task1Effects {
  @Effect() task1$: Observable<Action> = this.actions$
    .ofType('TASK1')
    .switchMap((action: Action1) =>
      this.service1.doSomething(action.param1)
        .map((result) => new Action1Success(result))
        // https://www.learnrxjs.io/operators/error_handling/catch.html
        // Remember to return an observable from the catch function!
        .catch((e: Error) => Observable.of(new Action1Error(e.message)))
    );
}