ngrx_user.effect.ts

@Injectable()  
export class UsersEffect {  
  constructor(  
    private actions$: Actions,  
    private usersService: UsersService  
  ) {}  
  
  @Effect()  
  loadUsers$ = this.actions$  
    .ofType(usersActions.LOAD_USERS)  
    .pipe(switchMap(() => {  
        return this.usersService.getUsers().pipe(  
          map((users: Users.List) => new usersActions.LoadUsersSuccess(users)),  
          catchError(error => of(new usersActions.LoadUsersFail(error)))  
        );  
      })  
    );  
  
}