如何在 get Reducers(): ActionReducerMap<fromFeature.State> 中 return reducer 映射？

Question

我试图在通过 NgRx 功能模块组合状态时注入 功能缩减器。

import { NgModule, InjectionToken } from '@angular/core';
import { StoreModule, ActionReducerMap } from '@ngrx/store';

import * as fromFeature from './reducers';

export const FEATURE_REDUCER_TOKEN = new InjectionToken<ActionReducerMap<fromFeature.State>>('Feature Reducers');

这里我应该return做什么？

export function getReducers(): ActionReducerMap<fromFeature.State> {
  // map of reducers
  return {
  
  };
}

我试过了

export function getReducers(): ActionReducerMap<fromFeature.State> {
      // map of reducers
      return {
          reducerA: FeatureAReducer
      };
    }

但它给出错误对象文字可能只指定已知属性。

其余模块代码：

@NgModule({
  imports: [
    StoreModule.forFeature('feature', FEATURE_REDUCER_TOKEN),
  ],
  providers: [
    {
      provide: FEATURE_REDUCER_TOKEN,
      useFactory: getReducers
    }
  ]
})
export class FeatureModule { }

Answer 1

我以为每个reducer，不管是root还是feature reducer，returns一个新的状态对象。但实际上并非如此。 feature reducer 的作用是，它 returns 仅更新状态的一部分。

来自ngrx/platform/example-app：

we treat each reducer like a table in a database. This means our top level state interface is just a map of keys to inner state types.

如何在 get Reducers(): ActionReducerMap<fromFeature.State> 中 return reducer 映射？

How to return a map of reducers in getReducers(): ActionReducerMap<fromFeature.State>?

ngrx

ngrx-store