RxJS：未达到地图功能

Question

我已经实现了这个功能：

public deleteCards(user: string, tokens: Array<string>, extraHttpRequestParams?: any): Observable<{}> {
    return this.deleteCardsWithHttpInfo(user, tokens, extraHttpRequestParams)
        .map((response: Response) => {
            if (response.status === 204) {
                return undefined;
            } else {
                return response.json();
            }
        }).catch((error: any) => {
            if (error.status >= 500) {
                return Observable.throw(new Error(error.status));
            }
            else { //if (error.status >= 400) {
                const body = error.json() || '';
                const code = body.error || JSON.stringify(body);
                const message = body.message || JSON.stringify(body);
                return Observable.throw(ApiError.create(code, message));
            }
        });
}

如您所见，它会返回Observable<{}>。我称之为：

this.deleteCards(action.payload.username, action.payload.tokens)
      .map(() => {   ((((1))))
        return <Action>{
          type: 'DELETE_CARDS_SUCCESS',
          payload: action.payload.tokens
        };
      })
      .catch(_ => {
        return Observable.of(<Action>{ type: 'DELETE_CARDS_FAILED', payload: { }});
      }));

然而，永远不会达到((((1))))。

我也试过这个：

1. .map(_ => { ...
2. .map((p:any) => {...

但它永远不会到达。

Answer 1

您必须订阅到observable才能执行任何操作：

this.deleteCards(...).map(...).catch(...).subscribe((action: Action) => {
    // do something with the action.
});