typescript 可选参数是泛型如何给其默认参数？

Question

export interface PageModelParams {
  pageIndex: number
  pageSize: number
}

export default function usePageModel<T extends Object, P extends PageModelParams = PageModelParams>(
  path: string,
  _params: P,
) {
  const [data, setData] = useState<T[]>([])
  const [params, setParams] = useState<P>(_params)

  /**
   * 拉数据
   */
  useEffect(
    function() {
      request
        .get<T[]>(path, {
          params,
        })
        .then(setData)
    },
    [params, path],
  )

  return {
    data,
    setParams,
  }
}

其中_params参数我想做成可选的，如果没有就用一个PageModelParams作为默认值
但是改为可选参数之后会显示'P' could be instantiated with a different subtype of constraint 'PageModelParams'