HarmonyOS 页面A跳转到页面B，参数传递里如何传递block

PageA：

router.pushUrl({
  url: 'class/pages/Launch/Index', params: {
    block: () => {

    }
  }
})

PageB：

let params: Map<string, Any> = router.getParams() as Map<string, Any>;
this.block = params["block"]

params[“block”]是undefined，PageA如何传递一个block给PageB？