Add a function to map from path to routeId (inverse of resolveRoute fn)

[thundergolfer]

Describe the problem

We have ?next=<path> routing in our app, and want to modify <path> on the basis of whether it is from a certain routeID. If the path does not match the relevant routeID, it is left unmodified.

Currently we hardcode a list of path prefixes that can't match the routeID. More generally, we would like to take advantage of SvelteKit's filesystem based routing to get a function that maps from a string path to its RouteID (if one exists).

This problem has come up before on Reddit: https://www.reddit.com/r/sveltejs/comments/14azrdg/how_can_i_determine_the_corresponding_route_id/

Describe the proposed solution

A function of the form getRouteIdByPathname(pathname: string) -> routeId: string, or a function of that provides not just the top matching route but the actual list of matches: https://kit.svelte.dev/docs/advanced-routing#sorting.

pathname	routeId
/signin	/(auth)/signin
/signup	/(auth)/signup
/forgot	/(auth)/forgot
/archive/1	/archive/[page]
/archive/2	/archive/[page]
/news/sport/1	/news/[type]/[page]
/news/music/1	/news/[type]/[page]

We could then do if (getRouteIdByPathname(nextPath) === "/news/[type]/[page]") { ... }.

Alternatives considered

• Keep maintaining the hardcoded list of path prefixes that shouldn't get modified

Importance

would make my life easier

Additional Information

No response

[mikerowe81]

I would also like this feature.

Perhaps something like:

function resolvePath(
    path: string
): {
    id: string
    params: Record<string, string | undefined>
};

e.g.

resolvePath("/blog/page1")

returns

{
    id: "/blog/[slug]",
    params: {
        slug: "page1"
    }
}

My use case is for route based permissions where I'd like to hide menu items or links if the user does not have permission to that route.

I'm sure the functionality is already built-in, it's just a matter of making the function public.

[ptrxyz]

And while we are at it: can we also make it so that resolveRoute's id auto-completes known ids? I saw that all the generated $types.d.ts files already contain RouteId. Something like so:

type AllRoutes = RouteId1 | RouteId2 | ... | (string & {})
//                                           ^^^^^^^^^^^^^ Always allow string
//               ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Imported from all $types.d.ts files
declare function resolveRoute(route: AllRoutes, params: Record<string, string>): string

[ptrxyz]

As a workaround I made this: https://www.npmjs.com/package/vite-plugin-svelte-typed-routes

// vite.config.ts
import vitePluginSvelteTypedRoutes from 'vite-plugin-svelte-typed-routes'
export default defineConfig({
  plugins: [
    vitePluginSvelteTypedRoutes({
      runPrettier: true
    }), 
    //other plugins here
  ]
})

Simply use resolveRoute and it will automagically autocomplete the routeId.