ngrx twice reducer call during effect - ngrx

Question

I am developing using an angular app using ngrx. I have defined the convention below to implement a loading indicator:
Initially state of each entity is set to null
Make it an empty object on effect starts
Fill it with fetched data on effect done
Now one of my effects will be this:
#Effect()
LoginUser$ = this._actions$.pipe(
ofType<LoginUser>(EUserActions.LoginUser),
switchMap((params) => { new LoginUserSuccess(<IUser>{}); return of(params); }), // for loading indicator to be shown
switchMap((params) => this._userService.loginUser(params.payload)),
switchMap((currentUser: IUser) => of(new LoginUserSuccess(currentUser)))
)
but the reducer call in the first switchMap does not get occur. What is the problem.

Answer 1

An effect is a stream, only the last Action in the stream will be dispatched.
For your case you can listen on LoginUser in your reducer and empty your state.

Answer 2

I have finally solved my problem some other way. I now am dispatching another action, inside the primary action to update the state. For example this is how I have done it:
user.service.ts
export class UserService {
constructor(private _store: Store<IAppState>) { }
loginUser(model): void {
this._store.dispatch(new AddBusy(EUserActions.LoginUser));
this._store.dispatch(new LoginUser(model));
}
getAllUsers(): void {
this._store.dispatch(new AddBusy(EUserActions.GetAllUsers));
this._store.dispatch(new GetAllUsers());
}
}
user.actions.ts
export class UserEffects {
#Effect()
LoginUser$ = this._actions$.pipe(
ofType<LoginUser>(EUserActions.LoginUser),
switchMap((params) => this._userLogic.loginUser(params.payload)),
switchMap((currentUser: IUser) => { this._store.dispatch(new RemoveBusy(EUserActions.LoginUser)); return of(currentUser); }),
switchMap((currentUser: IUser) => of(new LoginUserSuccess(currentUser)))
)
#Effect()
getAllUsers$ = this._actions$.pipe(
ofType<GetAllUsers>(EUserActions.GetAllUsers),
switchMap(() => this._userLogic.getAllUsers()),
switchMap((users: IUser[]) => { this._store.dispatch(new RemoveBusy(EUserActions.GetAllUsers)); return of(users); }),
switchMap((users: IUser[]) => of(new GetAllUsersSuccess(users)))
)
constructor(
private _userLogic: UserLogic,
private _actions$: Actions,
private _store: Store<IAppState>,
) { }
}
This solved my problem nice.