TypeScript函数参数约束与结果推断：如何解决类型推断不准确的问题？

type path2params = {
  '/order/detail': { orderid: string };
  '/product/list': { type: string; pagesize: string; pageno: string };
};

const orderparams: path2params['/order/detail'] = { orderid: '123' };
const productlistparams: path2params['/product/list'] = { type: 'electronics', pagesize: '10', pageno: '1' };

type buildquerystring<tparams extends record<string, string>> = {
  [k in keyof tparams]: `${extract<k, string>}=${tparams[k]}`;
}[keyof tparams];

type fullurl<
  tpath extends string,
  tparams extends record<string, string>,
> = `${tpath}${tparams extends record<string, never> ? '' : '?'}${buildquerystring<tparams>}`;

function buildstringwithparams<tpath extends keyof path2params, tparams extends path2params[tpath]>(
  path: tpath,
  params: tparams,
): fullurl<tpath, tparams> {
  const encodedparams = object.entries(params).map(([key, value]) => {
    const encodedvalue = encodeuricomponent(value);
    return `${encodeuricomponent(key)}=${encodedvalue}`;
  });
  const querystring = encodedparams.join('&');
  return `${path}${querystring ? '?' : ''}${querystring}` as fullurl<tpath, tparams>;
}

type UnionToIntersection<U> = (U extends any ? (k: U) => void : never) extends (k: infer I) => void
  ? I
  : never;

type UnionToTuple<U> =
  UnionToIntersection<U extends any ? () => U : never> extends () => infer R
    ? [...UnionToTuple<Exclude<U, R>>, R]
    : [];

type JoinWithAmpersand<T extends any[]> = T extends [
  infer First extends string,
  ...infer Rest extends string[],
]
  ? Rest extends []
    ? First
    : `${First}&${JoinWithAmpersand<Rest>}`
  : '';

type FinalBuildQueryString<T extends Record<string, string>> = JoinWithAmpersand<
  UnionToTuple<BuildQueryString<T>>
>;

type FullUrl<
  TPath extends string,
  TParams extends Record<string, string>,
> = `${TPath}${TParams extends Record<string, string> ? `?${FinalBuildQueryString<TParams>}` : ''}`;

// ......
const orderUrl = buildStringWithParams('/order/detail', orderParams);
const productListUrl = buildStringWithParams('/product/list', productListParams);