object-context

Object Context manages the cache of domain models in your Angular Application.

Object Context

The Object Context takes full control over the state of models sent and received via API and within the application cache.

Install

npm i @edorex/object-context

Get started

Register ObjectContext names

Add the name of your ObjectContext to the file object-context-name.class.ts.

If the file doesn't exist - create a new file to the core module dir (eg: src/app/core/object-context-name.class.ts)

export class ObjectContextName {
  public static readonly yourModelCtx = 'YourModelCtx';
}

Register Context provider

Register your own Object Context Services in the CoreModule.

@NgModule({
  // ...
  providers: [
    {
      provide: ObjectContextName.yourModelCtx,
      useFactory: (ctxService: ContextService) => new ObjectContext<YourModel>(ctxService),
      deps: [ContextService],
    }
  // ...
})
export class CoreModule { }

Create your service to access the ObjectContext

Create your service class and add public methods to call the ObjectContext ensure$ method like in the example below:

export class YourService {
  yourModel$: Observable<ObjectState<YourModel>>;

  constructor(
    @Inject(ObjectContextName.yourModelCtx) private yourModelCtx: ObjectContext<YourModel>,
    private yourModelApiService: YourModelApiService
  ) {
    this.yourModel$ = this.yourModelCtx.current$;
  }

  ensureYourModel$(): Observable<ObjectState<YourModel>> {
    return this.yourModelCtx.ensure$({
      execute: (current) => {
        return this.yourModelApiService.getAllHTTP().pipe(
          map((apiResponse: YourApiModel) => {
            return YourModel.from(apiResponse);
          })
        );
      },
      force: () => false,
      clear: () => false,
      queue: () => false,
    });
  }
}

Usage in Components

You just have to call yourService.ensure$() to get your Observable<ObjectState<YourModel>>. Checkout the source code in the demo project for more detail.

export class YourComponent implements OnInit {

  constructor(private yourService: YourService) { }

  ngOnInit(): void {
    this.yourService.ensureYourModel$().subscribe((state: ObjectState<YourModel>) => {
      if (state.isLoaded) {
        const model = state.object; // <-- Model received
      }
    });
  }
}

Note: For easier reading the observables' unsubscribe call is missing in the example above.