NGRX：创建多个减速器反应的“全局”动作的正确方法是什么？

Question

声明 ActionReducerMap 中的所有减速器都可以对其做出反应的“INIT_ACTION”的正确方法是什么？

这是我的代码如何的示例，我需要所有 3 个减速器（图像、标签、已添加标签）来对单个操作做出反应：

import { ActionReducerMap, createFeatureSelector } from '@ngrx/store';

import * as fromRoot from '../../../store';

import * as fromImages from './image.reducer';
import * as fromTags from './tag.reducer';
import * as fromAddedTags from './added-tag.reducer';

export interface AnalysisState {
    images: fromImages.State;
    tags: fromTags.State;
    addedTags: fromTags.State;
}
export interface State extends fromRoot.State {
    analysis: AnalysisState;
}

export const reducers: ActionReducerMap<AnalysisState> = {
    images: fromImages.reducer,
    tags: fromTags.reducer,
    addedTags: fromAddedTags.reducer
};

export const getAnlysisState = createFeatureSelector<AnalysisState>('analysis');

这是一个示例操作文件：

import { Action } from '@ngrx/store';
import { Tag } from '../../models/tag.model';

export const enum AddedTagActionTypes {
    ADD_TAG = '[ANALYSIS] - Add Tag'
}

export class AddTag implements Action {
    readonly type = AddedTagActionTypes.ADD_TAG;
    constructor(public payload: Tag) {}
}

export type AddedTagActions = AddTag;

这是一个示例减速器：

import { EntityState, EntityAdapter, createEntityAdapter } from '@ngrx/entity';

import * as fromAddedTag from '../actions/added-tag.actions';
import { Tag } from '../../models/tag.model';

export interface State extends EntityState<Tag> {}
export const adapter: EntityAdapter<Tag> = createEntityAdapter<Tag>({
    selectId: tag => tag.id
});

export const initialState: State = adapter.getInitialState({});
export function reducer(state = initialState, action: fromAddedTag.AddedTagActions): State {
    switch (action.type) {
        case fromAddedTag.AddedTagActionTypes.ADD_TAG: {
            return adapter.addOne(action.payload, state);
        }

        default: {
            return state;
        }
    }
}
const { selectIds, selectEntities, selectAll, selectTotal } = adapter.getSelectors();


export const getAllAddedTags = selectAll;

Answer 1

一个动作通过所有的减速器。因此，如果您只是在所有 3 个减速器中为该操作添加一个 case 语句，那么它将命中所有 3 个 case 语句。

如果在 reducer 中没有针对特定操作的 case 语句，则将触发默认的 case 语句，该语句仅返回原始状态，保持不变。

这假设您不是延迟加载减速器。减速器当然只有在加载时才会被触发。