config.md

Collection Service - Configuration

There is two ways to configure your CollectionService :

• With the CollectionConfig decorator.
• By overriding default getter of CollectionService.

CollectionConfig

CollectionConfig gives you an elegant way to define the configuration of your service :

@CollectionConfig({
  path: 'movies',
  idKey: 'name'
})

CollectionConfig accept a Partial<CollectionOptions> object as parameter that looks like that :

export interface CollectionOptions {
  path: string; // The path of the collection in Firestore
  idKey: string; // The key to use as an id for the document in Firestore. Default is store.idKey
}

Path Getter

Sometime the path is dynamic. If your service is targetting a subcollection, the path needs to know what is the id of the parent document.

In this case you'll need to override the path getter inside the class. Let's see how to do that with a Stakeholder of a specific movie :

@Injectable({ providedIn: 'root' })
export class StakeholderService extends CollectionService<StakeholderState> {
  constructor(store: StakeholderStore, private movieQuery: MovieQuery) {
    super(store);
  }

  get path() {
    const movieId = this.movieQuery.getActiveId();
    return `movies/${movieId}/stakeholders`;
  }
}

1. We do not need the CollectionConfig here.
2. We inject MovieQuery, the query of the parent collection.
3. We override the path getter by getting the active movie Id.

Path Observable

path can also be an observable. That way, sync is always going to be up-to-date with the state of your app.

To do that use selectActiveId instead of getActiveId :

export class StakeholderService extends CollectionService<StakeholderState> {
  ...
  get path() {
    return this.movieQuery.selectActiveId().pipe(
      map(movieId => `movies/${movieId}/stakeholders`)
    );
  }
}