Cannot read property 'map' of undefined using angular with ngrx

Question

I need help to understand this error that happens when I try to use an Observable array that comes from store.

this is the console error

ERROR TypeError: Cannot read property 'map' of undefined
    at ngrx-entity.js:67
    at ngrx-store.js:1198
    at memoized (ngrx-store.js:1039)
    at defaultStateFn (ngrx-store.js:1079)
    at ngrx-store.js:1207
    at memoized (ngrx-store.js:1039)
    at ngrx-store.js:1198
    at memoized (ngrx-store.js:1039)
    at defaultStateFn (ngrx-store.js:1079)
    at ngrx-store.js:1207

here is where I make the dispatch and try to use the Observable

  template: `
    <bc-patient-search> </bc-patient-search>
    <ngx-spinner [fullScreen]="false"></ngx-spinner>
    <bc-patient-preview-list [patients]="vm$ | async">
    </bc-patient-preview-list>
  `,
})
export class FindPatientPageComponent {
  patients$: Observable<Patient[]>;
  vm$ : Observable<Patient[]>;
  
  constructor(
    private store: Store<fromPatients.PatientsState>,
    private apiPatientService: ApiPatientsService,
    private spinner: NgxSpinnerService
  ) {  
    this.vm$ = store.pipe(select(fromPatients.selectPatientsTotal));
  }

  ngOnInit() {
    this.spinner.show();
    this.patients$ = this.apiPatientService.searchPatientList();
    this.loadPatients();
    setTimeout(() => {
      this.spinner.hide();
    }, 2000);
  }

  loadPatients() {
    this.store.dispatch(PatientLoadActions.loadPatients());
  }
}

here is selector

export const selectPatientsTotal = createSelector(
  selectAllPatients,
  patients => patients.filter(patients => patients != null && patients != undefined)
);

export const selectAllPatients = createSelector(
  selectPatientState,
  fromPatients.selectAll
);

and reducer

  on(PatientLoadActions.loadPatientsSuccess, (state, action) =>
    adapter.setAll(action.patients, state)
  ),

score 0 · Answer 1 · answered Mar 12 '21 at 20:51

Is it a feature store? Then you need to create your base feature selector as such:

export const selectPatientsState = createFeatureSelector(patientsFeatureKey);

Compare https://ngrx.io/guide/entity/adapter, the last code snippet (index.ts). I think I remember the same error from my first usage of ngrx entity.

Cannot read property 'map' of undefined using angular with ngrx

1 Answers1