Better support for extending NgxsDataEntityCollectionsRepository

[bitflut]

We recently switched from ngrx to nxgs with an app that heavily used ngrx/data. Right now we are trying to automate crud operations with our api in a similar way we did with ngrx/data. The route we've chosen is to extend NgxsDataEntityCollectionsRepository to include getAll getOne etc. for now.

Just to share what we are experiencing so far: If we are adding custom fields to the NgxsDataEntityCollectionsRepository reducer, we need to override get snapshot() and getState(). It'd be very nice, if there could be a third generic allowing to specify a type for the NgxsEntityCollections.

[splincode]

Give examples of expected behavior so that I can implement this

[bitflut]

I will put together a minimal example of what we're trying to achieve later today.

[bitflut]

Let's say we wanted additional properties in our EntityCollectionsReducer like loading and loaded:

export class MyCollectionRepository<V, K extends EntityIdType = EntityIdType>
    extends NgxsDataEntityCollectionsRepository<V, K> {

    @Computed()
    public get loading(): boolean {
        return this.snapshot.loading;
    }

    @Computed()
    public get loaded(): boolean {
        return this.snapshot.loaded;
    }

    @DataAction()
    public setLoading(@Payload('loading') loading: boolean): void {
        const state = this.getState();
        this.setEntitiesState({
            ...state,
            loading,
        });
    }

    @DataAction()
    public setLoaded(@Payload('loaded') loaded: boolean): void {
        const state = this.getState();
        this.setEntitiesState({
            ...state,
            loaded,
        });
    }
}

In order to get this working, there would be a few things we need to adjust. The most important is a new class type generic:

export class NgxsDataEntityCollectionsRepository<
    V,
    K extends number | string = EntityIdType,
    C extends NgxsEntityCollections<V, K> = NgxsEntityCollections<V, K>
>

Then we could simply use this in our Collection:

export class MyCollectionRepository<V, K extends EntityIdType = EntityIdType>
    extends NgxsDataEntityCollectionsRepository<V, K, MyCollection<V, K>>

There might be another caveat... for all the operations used in NgxsDataEntityCollectionsRepository, the rest of the state would need to be persisted. So addEntityOne would use this call to setEntitiesState:

        this.setEntitiesState({
            ...state,
            ids: [...state.ids, id],
            entities: { ...state.entities, [id]: entity },
        });

If this is hard to follow along, I can make an example repository with the overrides in place.

Edit:
Or would you rather suggest we implement something from scratch for this? Possibly NgxsDataEntityCollectionsRepository just wasn't supposed to support this case.

[splincode]

I understand you, yes, I think no problem will add this soon

[splincode]

### Extending NgxsDataEntityCollectionsRepository

move to Entity.md

[splincode]

released in v3.0.0-rc.14