如何使用选择器仅通过某个键获取数据?
也就是说,我有 4 个菜单,每个菜单都有一个特定catalogCode
的 ,用户在单击时从服务器获取特定菜单的列表。此列表的每个元素都有一个id = code + catalogCode
. 也就是说,catalogCode
这个菜单的所有元素都是相同的。那么如何catalogCode
从商店中获取特定商品的列表呢?
我正在尝试这样做:selectByCatalogCode
export const selectCatalogItemState: MemoizedSelector<object, State> = createFeatureSelector('CatalogItem');
export const selectCatalogItemAll: MemoizedSelector<object, CatalogItem[]> = createSelector(selectCatalogItemState, selectAll);
export const selectByCatalogCode = () => createSelector(selectCatalogItemAll, (entities: CatalogItem[], props: { catalogCode: string }) => entities[props.catalogCode]);
但这在组件中使用时不起作用,总是显示未定义的值
getCatalogItems(catalogCode: string) {
this.catalogItemStore.dispatch(new CatalogItemStoreAction.LoadByCatalog({catalogCode: catalogCode}));
this.catalogItemStore.select(CatalogItemStoreSelector.selectByCatalogCode(), {catalogCode: catalogCode}).subscribe(
a => console.log(a)
);
}
目录项.ts
export class CatalogItem {
constructor(public code: string,
public catalogCode: string,
public title: string,
public data: object) {
}
}
我只提供了部分代码。如有需要,我可以提供整个店铺的代码。
效果.ts
@Effect()
getCatalogEffect$: Observable<Action> = this.action$
.pipe(
ofType<featureAction.GetByCatalog>(featureAction.ActionTypes.GET_BY_CATALOG),
switchMap(action => this.store.select(CatalogItemStoreSelector.selectByCatalogCode(action.payload.catalogCode))
.pipe(
take(1),
filter(catalogItems => !catalogItems),
map(() => new featureAction.LoadByCatalog({catalogCode: action.payload.catalogCode})),
)
)
);
@Effect()
loadByCatalog$: Observable<Action> = this.action$
.pipe(
ofType<featureAction.LoadByCatalog>(featureAction.ActionTypes.LOAD_BY_CATALOG),
switchMap(action => this.catalogItemService.listByCatalog(action.payload.catalogCode)
.pipe(
map(catalogItems => new featureAction.LoadByCatalogSuccess({catalogItems: catalogItems})),
catchError(error => of(new featureAction.LoadByCatalogError({error: error}))),
)
)
);
目录-list.component.ts
getCatalogItems(catalogCode: string) {
this.catalogItemStore.dispatch(new CatalogItemStoreAction.GetByCatalog({catalogCode: catalogCode}));
}