Question

我有一个http服务调用，在调度时需要两个参数：

@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效果中的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有效内容：

@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toPayload中的ngrx/effects函数来映射操作的有效负载：

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，实用程序函数toPayload已被删除，自@ ngrx / effects v4.0以来已弃用。

有关详细信息，请参阅：https://github.com/ngrx/platform/commit/b390ef5

现在（自v5.0起）：

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

实施例：

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

在：

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？

2 个答案: