Angular 错误类型错误：无法读取属性'；数据'；减速器中未定义的参数

我得到以下错误：

错误类型错误：无法读取未定义的属性“数据”

缩减器文件：

import * as PfaAction from '../actions/profilefunctionarea.actions';
import { Action, createSelector, createFeatureSelector } from "@ngrx/store";
import { AppAction } from 'src/app/app.action';
import { Pfa } from '../shared/pfa';

export interface State {
    data: Pfa[];
}

const initialState: State = {
    data: [],
};

export function reducer(state = initialState, action: AppAction) {
    switch(action.type) {
        case PfaAction.GET_PROFILEFUNCTIONAREA:
            return {
                ...state,
                action: PfaAction.GET_PROFILEFUNCTIONAREA
            }
    }
}

export const getPfaState = createFeatureSelector < State > ('pfas');
export const getAllPfas = createSelector(getPfaState, (state: State) => state.data); <-- here getting error

动作。ts:

import { Pfa } from 'src/app/ngrx/shared/pfa';

pfas: Observable<Pfa[]>;
ngOnInit() {
    this.pfas = this.store.select(getAllPfas);
}

<select *ngFor="let pfa of pfas | async">
   <option value="pfa.id">{{pfa.area}}</option>
</select>

export class Pfa {
    id: number;
    area: string;
}

import { Action } from '@ngrx/store';
import { ProfileFunctionArea } from 'src/app/_interface/profilefucntionarea.module';
import { Pfa } from '../shared/pfa';

export const GET_PROFILEFUNCTIONAREA = '[ALL] Profile Function Area';
export const GET_PROFILEFUNCTIONAREA_SUCCESS = '[ALL] Profile Function Area Success';
export const GET_PROFILEFUNCTIONAREA_ERROR = '[ALL] Profile Function Area Error';

export class GetProfileFunctionArea implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA;
}

export class GetProfileFunctionAreaSuccess implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA_SUCCESS;
    constructor(public payload: Pfa[]) { }
}

export class GetProfileFunctionAreaError implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA_ERROR;
    constructor(public payload: Error) { }
}

@Injectable()
export class ProfileFunctionAreaEffects {
    constructor(private actions$: Actions, private ps: ProfileService) { }

    @Effect() GetProfileFunctionArea$: Observable<Action> = this.actions$.pipe( ofType(PfaAction.GET_PROFILEFUNCTIONAREA),
    switchMap(() => this.ps.GetProfileFunctionAreaGet()),
    map(items => new GetProfileFunctionAreaSuccess(items)), <-- getting error here
    catchError((err) => [new GetProfileFunctionAreaError(err)]));

}

效果。ts:

import { Pfa } from 'src/app/ngrx/shared/pfa';

pfas: Observable<Pfa[]>;
ngOnInit() {
    this.pfas = this.store.select(getAllPfas);
}

<select *ngFor="let pfa of pfas | async">
   <option value="pfa.id">{{pfa.area}}</option>
</select>

export class Pfa {
    id: number;
    area: string;
}

import { Action } from '@ngrx/store';
import { ProfileFunctionArea } from 'src/app/_interface/profilefucntionarea.module';
import { Pfa } from '../shared/pfa';

export const GET_PROFILEFUNCTIONAREA = '[ALL] Profile Function Area';
export const GET_PROFILEFUNCTIONAREA_SUCCESS = '[ALL] Profile Function Area Success';
export const GET_PROFILEFUNCTIONAREA_ERROR = '[ALL] Profile Function Area Error';

export class GetProfileFunctionArea implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA;
}

export class GetProfileFunctionAreaSuccess implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA_SUCCESS;
    constructor(public payload: Pfa[]) { }
}

export class GetProfileFunctionAreaError implements Action {
    readonly type = GET_PROFILEFUNCTIONAREA_ERROR;
    constructor(public payload: Error) { }
}

@Injectable()
export class ProfileFunctionAreaEffects {
    constructor(private actions$: Actions, private ps: ProfileService) { }

    @Effect() GetProfileFunctionArea$: Observable<Action> = this.actions$.pipe( ofType(PfaAction.GET_PROFILEFUNCTIONAREA),
    switchMap(() => this.ps.GetProfileFunctionAreaGet()),
    map(items => new GetProfileFunctionAreaSuccess(items)), <-- getting error here
    catchError((err) => [new GetProfileFunctionAreaError(err)]));

}

@Injectable（）
导出类ProfileFunctionalEffects{
构造函数（私有操作$：操作，私有ps:ProfileService）{}
@Effect（）GetProfileFunctionArea$：Observable=this.actions$.pipe（类型为pfaaaction.GET\u PROFILEFUNCTIONAREA），
switchMap（（）=>this.ps.getProfileFunctionReaget（）），
映射（items=>newgetprofilefunctionreasuccess（items）），[newgetprofilefunctionreaerror（err）]；
}

这行代码是错误的

        return {
            ...state,
            action: PfaAction.GET_PROFILEFUNCTIONAREA
        }

你应该回来

        return {
            ...state,
            data: [] // add your array here
        }

---

reducer应始终返回状态，在代码段中，reducer将仅返回

PFAAAction.GET_PROFILEFUNCTIONAREA

的状态，并将返回

undefined

的其他每一个分派操作。这是因为一个动作将被分派到所有减速器

要解决此问题，请添加一个

默认值

案例：

export function reducer(state = initialState, action: AppAction) {
    switch(action.type) {
        case PfaAction.GET_PROFILEFUNCTIONAREA:
            return {
                ...state,
                action: PfaAction.GET_PROFILEFUNCTIONAREA
            }

       // add this
       default:
          return state;
    }
}

---

能否请您添加一些更多信息，如错误出现的位置、您试图实现的目标等。除此之外，我还没有使用ngrx等工具，但我看到了

。数据
可在reducer file
createSelector
函数中访问。因此，
状态
可能未定义。但，这个问题必须更详细，以便有人回答。@kiranghule27在试图获取component.html文件中的列表时，我得到了那个错误！让我试试这个。哪个数组？Pfa[]数据数组来自您的有效负载。你知道redux是如何工作的吗？我试图理解但没有得到它添加的两个文件代码，但是我在
effects.ts
中得到错误，这一行
map（items=>new getProfileFunctionarAsccess（items）），
用于items