withLinkEntitiesSingleSelection

Experimental. Ready to use, but the API may still change in response to feedback. If you hit a problem or something feels awkward, please open an issue.

Generates a link[Collection]IdSelected() method that connects the selected entity id to component signals like input(), model() and Angular Signal Forms. Prebuilt version of withLink for withEntitiesSingleSelection: writes route through select[Collection]Entity / deselect[Collection]Entity (setting null deselects). No selection always reads as null, never undefined, so Signal Forms keeps the field instead of dropping it.

It emits Id | null but accepts Id | null | undefined: a signal it reads from (readFrom, e.g. an input()) can be undefined-typed with no map, while one it writes to (syncWith, writeTo) must accept null, or pass writeMap: (id) => id ?? undefined.

Requires withEntitiesSingleSelection to be used before it.

Examples

Two-way sync with a model()

const productEntityConfig = entityConfig({
  entity: type<Product>(),
  collection: 'product',
});

export const ProductsStore = signalStore(
  { providedIn: 'root' },
  withEntities(productEntityConfig),
  withEntitiesSingleSelection(productEntityConfig),
  // generates linkProductIdSelected()
  withLinkEntitiesSingleSelection(productEntityConfig),
);

@Component({
  /* ... */
})
export class ProductSelectComponent {
  store = inject(ProductsStore);

  // writes from the parent select the entity in the store,
  // selecting in the store updates the parent
  selectedId = model<Product['id'] | null>(null);
  linked = this.store.linkProductIdSelected({ syncWith: this.selectedId });
}

As a form field

export class ProductSelectComponent {
  store = inject(ProductsStore);

  // reads store.productIdSelected(),
  // writing selects/deselects the entity
  selectedField = form(this.store.linkProductIdSelected());
}

API

withLinkEntitiesSingleSelection({ entity, collection? })

Property	Description	Type
entity	The entity type	type()
collection	The name of the collection (optional)	string

Methods

Id is the id type of the withEntitiesSingleSelection before it: the return type of its config's selectId (string | number with the ngrx entityConfig), or else the entity's id prop type.

// link[Collection]IdSelected(options?) => WritableSignal<Id | null>
{
  linkIdSelected: (options?) => WritableSignal<Id | null>;
  // or with collection 'product':
  linkProductIdSelected: (options?) => WritableSignal<Id | null>;
}

See withLink for the options parameter (syncWith, readFrom, writeTo, readMap, writeMap, initialValueFrom, storeEditsWhen).

This feature passes noSetter: true, so no private _set method is generated — select/deselect[Collection]Entity already covers that write.

State

No state signals are generated.

Props

No props are generated.