Angular 2 - Show loading-information when (observableData | async) is not yet resolved

This is how I do it. Also i use $ at the and of the variable name to remind me that it is a stream.

// dataview.html
<div *ngIf="isLoading$ | async">Loading data...</div>
<ul *ngIf="!(isLoading$ | async)">
    <li *ngFor="let d of data">{{ d.value }}</li>
</ul>


// dataview.ts

data: any[] = [];
isLoading$: BehaviorSubject<boolean> = new BehaviorSubject(false);

getData() {

this.isLoading$.next(true);

this._api.getData().subscribe(
        data => {
            this.data = data;
        },
        error => {
            this.error = error;
        },
        complete => {
            this.isLoading$.next(false);
        });
}

I Came up with the following:

export enum ObsStatus {
  SUCCESS = 'Success',
  ERROR = 'Error',
  LOADING = 'Loading',
}

export interface WrapObsWithStatus<T> {
  status: ObsStatus;
  value: T;
  error: Error;
}

export function wrapObsWithStatus<T>(obs: Observable<T>): Observable<WrapObsWithStatus<T>> {
  return obs.pipe(
    map(x => ({ status: ObsStatus.SUCCESS, value: x, error: null })),
    startWith({ status: ObsStatus.LOADING, value: null, error: null }),
    catchError((err: Error) => {
      return of({ status: ObsStatus.ERROR, value: null, error: err });
    })
  );
}

And then in your component:

TS

public ObsStatus: typeof ObsStatus = ObsStatus;

public obs$: Observable<WrapObsWithStatus<YOUR_TYPE_HERE>> = wrapObsWithStatus(this.myService.getObs());

HTML

<div *ngIf="obs$ | async as obs" [ngSwitch]="obs.status">
  <div *ngSwitchCase="ObsStatus.SUCCESS">
    Success! {{ obs.value }}
  </div>

  <div *ngSwitchCase="ObsStatus.ERROR">
    Error! {{ obs.error }}
  </div>

  <div *ngSwitchCase="ObsStatus.LOADING">
    Loading!
  </div>
</div>

I did it by using the async pipe. But this approach still required you to catch it manually to handle the error. See here for more detail.

app.component.html

<div class="wrapper">
    <div class="form-group" *ngIf="pickupLocations$ | async as pickupLocations; else loading">    
        <ul class="dropdown-menu" *ngIf="pickupLocations.length">
            <li *ngFor="let location of pickupLocations">
                <strong>{{location.Key}}</strong>
            </li>
        </ul>
        <span *ngIf="!pickupLocations.length">There are no locations to display</span>
    </div>

    <ng-template #loading>
        <i class="fa fa-circle-o-notch fa-spin fa-3x fa-fw"></i>
        <span class="sr-only">Loading...</span>
    </ng-template>
</div>

app.component.ts

this.pickupLocations$ = this.apiService.getPickupLocations(storeId);