如何在 Angular 2 中访问 ngrx 效果中的参数？

Question

我有一个 http 服务调用，在发送时需要两个参数：

@Injectable()
export class InvoiceService {
  . . .

  getInvoice(invoiceNumber: string, zipCode: string): Observable<Invoice> {
    . . .
  }
}

我如何随后将这两个参数传递给我的 Effect 中的 this.invoiceService.getInvoice()？

@Injectable()
export class InvoiceEffects {
  @Effect()
  getInvoice = this.actions
    .ofType(InvoiceActions.GET_INVOICE)
    .switchMap(() => this.invoiceService.getInvoice())  // need params here
    .map(invoice => {
      return this.invoiceActions.getInvoiceResult(invoice);
    })
}

Answer 1

您可以在操作中访问负载：

@Injectable()
export class InvoiceEffects {
  @Effect()
  getInvoice = this.actions
    .ofType(InvoiceActions.GET_INVOICE)
    .switchMap((action) => this.invoiceService.getInvoice(
      action.payload.invoiceNumber,
      action.payload.zipCode
    ))
    .map(invoice => this.invoiceActions.getInvoiceResult(invoice))
}

或者您可以使用 ngrx/effects 中的 toPayload 函数来映射操作的负载：

import { Actions, Effect, toPayload } from "@ngrx/effects";

@Injectable()
export class InvoiceEffects {
  @Effect()
  getInvoice = this.actions
    .ofType(InvoiceActions.GET_INVOICE)
    .map(toPayload)
    .switchMap((payload) => this.invoiceService.getInvoice(
      payload.invoiceNumber,
      payload.zipCode
    ))
    .map(invoice => this.invoiceActions.getInvoiceResult(invoice))
}

Answer 2

在@ngrx/effects v5.0 中，效用函数toPayload 被删除，自@ngrx/effects v4.0.

以来它已被弃用

详情见：https://github.com/ngrx/platform/commit/b390ef5

现在（自 v5.0 起）：

actions$.
  .ofType('SOME_ACTION')
  .map((action: SomeActionWithPayload) => action.payload)

示例：

@Effect({dispatch: false})
printPayloadEffect$ = this.action$
    .ofType(fromActions.DEMO_ACTION)
    .map((action: fromActions.DemoAction) => action.payload)
    .pipe(
        tap((payload) => console.log(payload))
    );

之前：

import { toPayload } from '@ngrx/effects';

actions$.
  ofType('SOME_ACTION').
  map(toPayload);

如何在 Angular 2 中访问 ngrx 效果中的参数？

How to access parameters in an ngrx effect in Angular 2?

ngrx

angular