Proper typing of unionEntitiesAsMap()

[hakimio]

I would like to fix unionEntitiesAsMap return value typing so that instead of Record<string, T['entities'][0] & T['UIEntities'][0]>, it would return Record<getIdType<S, Ref>, T['entities'][0] & T['UIEntities'][0]>, but I don't really understand how getIdType<S, Ref> can be used in this case.
@NetanelBasal Could you give me some hints?

[NetanelBasal]

Try to use the idKey type directly

[hakimio]

Ok, theoretically I understand what should be done, but still can't get exactly the right results.
Following:

export function unionEntitiesAsMap<
  T extends {
    entities: Record<string, any>[];
    UIEntities: Record<string | number, Record<string, any>>;
  }
>(
  idKey: keyof T['entities'][0] = 'id'
): OperatorFunction<T, Record<T['entities'][0][typeof idKey], T['entities'][0] & T['UIEntities'][0]>> {
  return map((state: T) => {
    return Object.fromEntries(
      state.entities.map((entity) => {
        return [
          entity[idKey as string],
          {
            ...entity,
            ...state.UIEntities[entity[idKey as string]],
          },
        ];
      })
    );
  });
}

when used as follows:

enum FooBar {A, B, C}
export interface Foo {
  id: FooBar;
  title: string;
  completed: boolean;
}
export interface UIFoo {
  id: FooBar;
  open: boolean;
}

const { state, config } = createState(
      withEntities<Foo>(),
      withUIEntities<UIFoo>()
    );

const store = new Store({ state, name: 'todos', config });

const fooMap$ = store
      .combine({
        entities: store.pipe(selectAll()),
        UIEntities: store.pipe(selectEntities({ ref: UIEntitiesRef })),
      })
      .pipe(unionEntitiesAsMap('id'));

doesn't give me the expecpected typing of fooMap$: Observable<Record<FooBar, Foo & UIFoo>>.

What should I use instead of the following mess:

OperatorFunction<T, Record<T['entities'][0][typeof idKey], T['entities'][0] & T['UIEntities'][0]>>

[NetanelBasal]

I don't have much time for this. If it's an issue for you, we can switch to any for now.

[hakimio]

No worries. You can leave it as is for now if you don't know any simple solution. It's not a big deal.

[NetanelBasal]

import { OperatorFunction } from 'rxjs';
import { map } from 'rxjs/operators';

export function unionEntitiesAsMap<
  T extends {
    entities: Record<string, any>[];
    UIEntities: Record<string | number, Record<string, any>>;
  },
  Idkey extends keyof T['entities'][0] = 'id'
>(
  idKey: Idkey = 'id' as Idkey,
): OperatorFunction<T, Record<T['entities'][0][Idkey], T['entities'][0] & T['UIEntities'][0]>> {
  return map((state: T) => {
    return Object.fromEntries<
      Record<string, T['entities'][0] & T['UIEntities'][0]>
    >(
      state.entities.map((entity) => {
        return [
          entity[idKey as string],
          {
            ...entity,
            ...state.UIEntities[entity[idKey as string]],
          },
        ];
      })
    );
  }) as any;
}

[hakimio]

Thanks. It seems to work as expected. Should I create a PR?

[NetanelBasal]

Yes, update the specs please