从回调返回承诺

Question

我需要通过返回Observable来验证诺言，所以碰巧只有在“打开对话框”中单击“确认”时才返回此Observable。

我需要知道promise之外是否已完成callback。

我该如何以最佳方式做到这一点？

return dialog.afterClose.pipe(
    switchMap((reauthenticated) => {
        if (reauthenticated) {

            const confirmDelete = this._modalService.warning({
                nzTitle: 'Do you really want to delete this user?',
                nzContent: `When a user is deleted all related data
                                             it will be lost without any option and retrieve them.`,
                nzOkText: 'Confirm',
                nzCancelText: 'Cancel',
                nzOnCancel: () => {
                    confirmDelete.destroy();
                },
                nzOnOk: () => {
                    this._message.info('User deleted success.', {
                        nzDuration: 5000,
                        nzPauseOnHover: true,
                        nzAnimate: true
                    });

                    // Only returned if you click Confirm.
                    return Observable.fromPromise(userRef.delete());
                }
            });

            // I need to return if the promise was resolved
            // here instead of returning only when I clicked Confirm.

            setTimeout(() => {
                confirmDelete.destroy();
            }, 15000);
        } else {
            throw new Error('User not authenticated');
        }

    })
);