Question

什么是正确的方法来声明“ INIT_ACTION”？ ActionReducerMap可以做出反应吗？

这是我的代码如何运行的示例，我需要所有3个reducer（图像，标签，addedTags）来对一个动作做出反应：

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;

这是减速器的示例：

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

一个动作通过所有减速器。因此，如果您仅在所有3个reducer中都为该动作放置一个case语句，那么它将击中所有3个case语句。

如果reducer中没有针对特定操作的case语句，则将触发默认case语句，该语句仅返回原始状态，而不会对其进行修改。

这假定您不是延迟加载减速器。减速器当然只有在加载时才被触发。

NGRX：创建多个减速器反应的“全局”动作的正确方法？

1 个答案: