我如何在NGRX中的另一个异化器中访问(读取)异化器状态? 这是与this非常相似的问题。 NGRX是否为此提供其他解决方案?
答案 0 :(得分:0)
在考虑做类似的事情时,我偶然发现了这个问题。我需要从另一个化简器获取一些状态信息的副本,作为可以取消并恢复为“已记录”数据集的临时“编辑”数据集。
我最终扩展了我的UI缩减器(保留当前用户会话状态/编辑的缩减器),使其包含一个属性以保存来自数据缩减器(代表数据库中存储内容的缩减器)的数据副本)。这些数据是通过“开始”操作传递的。
这是我的UI操作的缩写副本:
import { Action } from "@ngrx/store";
import {
ICableFeature
} from "../../shared/models";
export enum UIActionTypes {
...
UI_EDIT_CUSTOM_TAGS_START = "[UI] Edit Custom Tags Start",
UI_EDIT_CUSTOM_TAGS_UPDATE = "[UI] Edit Custom Tags Update",
UI_EDIT_CUSTOM_TAGS_SAVE = "[UI] Edit Custom Tags Save",
UI_EDIT_CUSTOM_TAGS_SUCCESSFUL = "[UI] Edit Custom Tags Successful",
UI_EDIT_CUSTOM_TAGS_FAILED = "[UI] Edit Custom Tags Failed",
UI_EDIT_CUSTOM_TAGS_CANCELED = "[UI] Edit Custom Tags Canceled"
}
...
export class EditCustomTagsStart implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_START;
constructor(public payload: ICableFeature) {}
}
export class EditCustomTagsUpdate implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_UPDATE;
constructor(public payload: ICableFeature) {} // This payload has a copy of the data I needed from the other reducer. Make sure it is a copy and not the same object!
}
export class EditCustomTagsSave implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_SAVE;
constructor() {}
}
export class EditCustomTagsSuccessful implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_SUCCESSFUL;
constructor() {}
}
export class EditCustomTagsFailed implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_FAILED;
constructor(public payload: string) {}
}
export class EditCustomTagsCanceled implements Action {
readonly type = UIActionTypes.UI_EDIT_CUSTOM_TAGS_CANCELED;
constructor() {}
}
export type UIActions =
...
| EditCustomTagsStart
| EditCustomTagsUpdate
| EditCustomTagsSuccessful
| EditCustomTagsFailed
| EditCustomTagsCanceled;
这是我的UI reducer的缩写副本:
import * as fromUI from "../actions/ui.actions";
import {
IOrchestratorState,
IOrchestratorStatusState,
ICableFeature
} from "../../shared/models";
export const uiFeatureKey = "ui";
export interface State {
showScroll: boolean;
fillingGaps: boolean;
fillGapStatus: IOrchestratorStatusState;
currentFillGapState: IOrchestratorState;
editingCustomTags: boolean;
customTagEdits: ICableFeature;
}
export const initialState: State = {
showScroll: true,
fillingGaps: false,
fillGapStatus: null,
currentFillGapState: null,
editingCustomTags: false,
customTagEdits: null
};
export function reducer(state = initialState, action: fromUI.UIActions) {
switch (action.type) {
...
case fromUI.UIActionTypes.UI_EDIT_CUSTOM_TAGS_START:
return {
...state,
editingCustomTags: true,
customTagEdits: action.payload // This is a copy of the data I needed from the other reducer
};
case fromUI.UIActionTypes.UI_EDIT_CUSTOM_TAGS_UPDATE:
return {
...state,
customTagEdits: action.payload // This is the updated information from user edits, not saved.
// I can also create a router guard that checks to makes sure the data in this
// property and the data in my Data store are the same before the page is deactivated
};
case fromUI.UIActionTypes.UI_EDIT_CUSTOM_TAGS_SUCCESSFUL:
case fromUI.UIActionTypes.UI_EDIT_CUSTOM_TAGS_FAILED:
case fromUI.UIActionTypes.UI_EDIT_CUSTOM_TAGS_CANCELED:
return {
...state,
editingCustomTags: false,
customTagEdits: null
};
default:
return state;
}
}
如您所见,通过将数据作为操作中的有效负载从一个reducer传递到另一个reducer,我能够在我的reducer中维护纯函数。
我希望这会有所帮助!