新手问题:我有一个使用ngrx的angular2应用程序,我有一个服务返回状态(一组可观察对象)给组件。
我的问题是,如果我想在组件中使用只读子集进行过滤,那么我在哪里过滤状态?
我应该在reducer、service还是component中做呢?
可以在ngrx示例应用中找到一些指导。有一个模式是定义选择器与reducer一起定义:
/**
* Because the data structure is defined within the reducer it is optimal to
* locate our selector functions at this level. If store is to be thought of
* as a database, and reducers the tables, selectors can be considered the
* queries into said database. Remember to keep your selectors small and
* focused so they can be combined and composed to fit each particular
* use-case.
*/
export function getBookEntities() {
return (state$: Observable<BooksState>) => state$
.select(s => s.entities);
};
这些选择器被用于(智能)组件中来选择/过滤状态:
在这里查看代码示例...
export class CollectionPage {
books$: Observable<BooksInput>;
constructor(store: Store<AppState>) {
this.books$ = store.let(getBookCollection());
}
}
这种模式/机制可以用于过滤组件或服务中的状态 - 无论哪种最适合您的架构。