[Typescript] 92. Medium PathParams

type PathParams<S extends string> =
  S extends `/${string}/:${infer Param}/${infer REST}`
    ? Param | PathParams<`/${REST}`>
    : S extends `${string}/:${infer Param}`
    ? Param
    : never;

[
  Expect<Equal<PathParams<"/profile">, never>>,
  Expect<Equal<PathParams<"/profile/:userId">, "userId">>,
  Expect<
    Equal<PathParams<"/profile/:userId/posts/:postId">, "userId" | "postId">
  >,
];