NGRX | store.select（状态=> state.MyObject）| 返回未定义

Question

Situation, I'm trying to retrieve state info using the following approach:

listObject: Array<ListObject>;
this.list$ = this.store.select(state => state.MyListObject);
this.listSub$ = this.list$.subscribe(list => this.listObject = list);

This works for every component except a new component I created a couple days ago. The listSub$ subscription returns an undefined object. The kicker is I can see the state with my Redux DevTools. In state there are two objects in the MyListObject. At a login event, the store is dispatched to load the list; I can see the list load in Redux DevTools as well as logging statements.

I cannot figure out why this.store.select(state => state.MyListObject) returns undefined when state is present. Has anyone seen this issue before?

I made sure that StoreModule.forRoot({}) has my reducer referenced, and the effect I'm using is in the EffectsModule.forRoot([]).

The Problem Code

clatschList: ClatschList;
this.clatschList$ = this.store.select(state => state.ClatschList);
this.ClatschListSub = this.clatschList$.subscribe(list => this.clatschList = list);

MyListObject

export class ClatschList {
  public clatsches: Array<ClatschSummary> = [];
  public links: Array<Link> = [];
}

App State

export interface ClatschesAppState {
  ClatschList: ClatschList;
 }

Action

export type Action
  = LoadMemberClatsches
| LoadMemberClatschesSuccess;

export const LOAD_MEMBER_CLATCHES = 'LOAD_MEMBER_CLATCHES';
export class LoadMemberClatsches {
  readonly type = LOAD_MEMBER_CLATCHES;
  constructor() {}
}

export const LOAD_MEMBER_CLATCHES_SUCCESS = 'LOAD_MEMBER_CLATCHES_SUCCESS';
export class LoadMemberClatschesSuccess {
  readonly type = LOAD_MEMBER_CLATCHES_SUCCESS;
  constructor(public clatschList: ClatschList) {}
}

Reducer

export function MemberClatschesReducer(state: ClatschList = new 
ClatschList(), action: ClatschAction.Action) {

  switch (action.type) {
    case ClatschAction.LOAD_MEMBER_CLATCHES_SUCCESS: {
      return action.clatschList;
    }

    default: {
      return state;
    }
  }
}

Effect

  @Effect() LoadMemberClatschList$ = this.actions$
      .ofType(ClatschAction.LOAD_MEMBER_CLATCHES).pipe(
        switchMap((action: LoadMemberClatsches) =>
          this.clatschService.FindAllByMember().pipe(
            map(list => new ClatschAction.LoadMemberClatschesSuccess(list)))
        )
      );

Module

@NgModule({
  imports: [
    CommonModule,
    HttpClientModule,
    AuthorizationModule,
    StoreModule.forRoot(
               {  makerContext: makerContextReducer,
                  makers: makerReducer,
                  locations: locationsReducer,
                  locationSearchResult: locationSearchResultReducer,
                  locationSearchResultDetail: locationSearchResultDetailReducer,
                  events: MakerEventsReducer,
                  eventContext: EventContextReducer,
                  EventList: EventListReducer,
                  EventListPagination: EventListPaginationReducer,
                  SelectedEvent: SelectedEventReducer,
                  MemberClatschList: MemberClatschesReducer,
        }),
    EffectsModule.forRoot( [MakerEffect, LocationEffect, EventEffect, 
ClatschEffect]),
    StoreDevtoolsModule.instrument()
  ],
  declarations: [LocationSearchComponent],
  providers: [ MakerService,
    StorageService,
    EventService,
    LocationService,
    ClatschRepositoryService,
    ClatschService,
    ApiResourceService,
    LoggingService,
    UserNotificationService,
    HttpErrorHandlerService ]
})

export class CoreModule { }

Answer 1

Ok thanks for posting the rest of the code. I found your problem. In the module, you declared:

StoreModule.forRoot({  
    ...
    MemberClatschList: MemberClatschesReducer,
})

That means your app state will have a property MemberClatschList which will be handled by the MemberClatschesReducer , but both in the AppState interface and your component you called the property ClatschList . It always returns undefined because you're trying to access state.ClatschList , when in reality it should be state.MemberClatschList