没有nttx/effects的HttpHandler提供程序

Question

我正在尝试重新创建一个非常类似于ngrx文档的authEffect,并收到此错误消息: Error: StaticInjectorError(AppModule)[HttpClient -> HttpHandler]: StaticInjectorError(Platform: core)[HttpClient -> HttpHandler]: NullInjectorError: No provider for HttpHandler!

效果服务:

@Injectable()
export class HttpEffects {
  constructor(private http: HttpClient, private actions$: Actions) {}

  @Effect() login$: Observable<ActionWithPayload> = this.actions$.pipe(
    ofType(ActionTypes.SEND_LOGIN),
    mergeMap((action: ActionWithPayload) =>
      this.http.post(SERVER_URL + LOGINAPI.LOGIN, action.payload, config).pipe(
        map(data => ({type: 'LOGIN_SUCCESS', payload: data})),
        catchError(() => of({type: 'LOGIN_ERROR'}))
      ))
  );
}

app.module:

@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    BrowserModule,
    BrowserAnimationsModule,
    StoreModule.forRoot(rootReducer),
    StoreDevtoolsModule.instrument({
      maxAge: 10
    }),
    EffectsModule.forRoot([HttpEffects])
  ],
  exports: [
    BrowserAnimationsModule
  ],
  providers: [ HttpClient ],
  bootstrap: [AppComponent]
})

我也尝试在功能模型中导入效果服务EffectsModule.forFeature(),但是会抛出相同的错误.

Answer 1

如HttpClient文档中所述:

在使用HttpClient之前,需要安装提供它的HttpClientModule.这可以在您的应用程序模块中完成,只需要一次.

所以你必须导入HttpClientModule而不是HttpClient:

import { HttpClientModule } from '@angular/common/http';

@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    ...
    EffectsModule.forRoot([HttpEffects])
  ],
  exports: [
    BrowserAnimationsModule
  ],
  bootstrap: [AppComponent]
})