link.d.ts

declare module 'next' {
  export * from 'next/types/index.d.ts';
  type SearchOrHash = `?${string}` | `#${string}`

  type Suffix = "" | SearchOrHash

  type SafeSlug<S extends string> = 
    S extends `${string}/${string}`
      ? never
      : S extends `${string}${SearchOrHash}`
      ? never
      : S extends ''
      ? never
      : S

  type CatchAllSlug<S extends string> = 
    S extends `${string}${SearchOrHash}`
      ? never
      : S extends ''
      ? never
      : S

  type OptionalCatchAllSlug<S extends string> = 
    S extends `${string}${SearchOrHash}`
      ? never
      : S

  export type Route<T extends string = string> = 
   | `/privacy${Suffix}`
 | `/terms${Suffix}`
 | `/levels/calculator${Suffix}`
 | `/${Suffix}`
 | `/status${Suffix}`

}

declare module 'next/link' {
  import type { Route } from 'next'
  import type { LinkProps as OriginalLinkProps } from 'next/dist/client/link'
  import type { AnchorHTMLAttributes } from 'react'
  import type { UrlObject } from 'url'
  
  type LinkRestProps = Omit<Omit<AnchorHTMLAttributes<HTMLAnchorElement>, keyof OriginalLinkProps> & OriginalLinkProps, 'href'>;

  // If the href prop can be a Route type with an infer-able S, it's valid.
  type HrefProp<T> = T extends (Route<infer S> | UrlObject) ? {
    /**
     * The path or URL to navigate to. This is the only required prop. It can also be an object.
     *
     * https://nextjs.org/docs/api-reference/next/link
     */
    href: T
  } : {
    /**
     * The path or URL to navigate to. This is the only required prop. It can also be an object.
     *
     * https://nextjs.org/docs/api-reference/next/link
     */
    href: never
  }

  export type LinkProps<T> = LinkRestProps & HrefProp<T>
  export default function Link<RouteType>(props: LinkProps<RouteType>): JSX.Element
}