4. Arguments for your loader

If you want the loader to take an argument, all you have to do is to add a queriesArg:

import { ConsumerProps } from "@ryfylke-react/rtk-query-loader";

// This means that any component that has props that extend this
// type can consume the loader using `withLoader`
type UserRouteLoaderProps = ConsumerProps<{
  userId: string;
}>;

export const userRouteLoader = baseLoader.extend({
  queriesArg: (props: UserRouteLoaderProps) => props.userId,
  // type is now inferred from queriesArg return
  useQueries: (userId) => {
    const user = useGetUserQuery(userId);
    const posts = useGetPostsByUser(userId);

    return {
      queries: {
        user,
        posts,
      },
    };
  },
});