Ngrx：结合两个选择器

Question

我建立了这个IStore：

export interface IStore {
  user: IUser;
  sources: ISourceRedux;
}

在哪里IUser：

export interface IUser {
    id: string;
    cname: string;
    sname: string;
    ...
}

并且ISourceRedux是：

export interface ISourceRedux {
    entities: { [key: string]: ISource };
    ids: Array<string>;
    selectedIds: Array<string>;
    editingSource: ISource;
    defaultId: string;
}

因此，我创建了以下选择器：

export const getSourcesState = (state: IStore) => state.sources;
export const getSelectedIds = (sourceRdx: ISourceRedux) => sourceRdx.selectedIds;
export const getSelectedSourceIds = createSelector(getSourcesState, fromSources.getSelectedIds);

因此，到目前为止，为了检查是否已登录用户，我这样做了：

this.store$
  .select(fromRoot.getUserState)
  .filter(user => user.id != null && user.logged)
  .do(user => this.store$.dispatch(...))
  ...

现在，我正在努力获取用户信息和selectedSourceIds，以便检查是否：

1. 用户已登录（this.store$.select(fromRoot.getUserState)
2. 然后获取所有selectedSourceIds（this.store.select(fromRoot.getSelectedSourceIds)）
3. 采取行动

我怎么能得到这个？

Answer 1

将该代码添加到选择器是否有意义：

// Selector functions
const getProductFeatureState = createFeatureSelector<ProductState>('products');
const getUserFeatureState = createFeatureSelector<UserState>('users');

export const getCurrentProduct = createSelector(
  getProductFeatureState,
  getUserFeatureState,
  getCurrentProductId,
  (state, user, currentProductId) => {
    if (currentProductId === 0) {
      return {
        id: 0,
        productName: '',
        productCode: 'New',
        description: 'New product from user ' + user.currentUser,
        starRating: 0
      };
    } else {
      return currentProductId ? state.products.find(p => p.id === currentProductId) : null;
    }
  }
);

此代码在product.reducer文件中。在这里，我为产品和用户定义了功能选择器。

然后，我getCurrentProduct同时使用产品和用户功能构建选择器。

Answer 2

这是我的解决方案：

this.store$.combineLatest(
      this.store$.select(fromRoot.getUserEntity),
      this.store$.select(fromRoot.getSelectedSourceIds),
      (store, user, selectedSourceIds) => ({user: user, selectedSourceIds: selectedSourceIds}) 
    )
    .filter((proj) => proj.user.id != null && proj.user.logged)
    .do((proj) => this.store$.dispatch({type: 'DELETE_CARDS', payload: {username: proj.user.username, tokens: proj.selectedSourceIds}}))
    .take(1)
    .subscribe();

我希望它有用。