ngRx ------Selectors一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第6天，点击查

一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第6天，点击查看活动详情。

selector 是纯函数用来获取state，

import { createSelector } from '@ngrx/store';

export interface FeatureState {
  counter: number;
}

export interface AppState {
  feature: FeatureState;
}

export const selectFeature = (state: AppState) => state.feature;

export const selectFeatureCount = createSelector(
  selectFeature,
  (state: FeatureState) => state.counter
);