breaking: remove param files in folder in favor of params.js/ts file

[dummdidumm]

Instead of having to declare one param matcher per file, you now declare all of them within one file. A defineParams function both helps with declaring them in a type-safe way and also normalizes the property values: You can either parse a standard schema object, or a function that either throws or returns the parsed value (if you don't want to bring in a schema library).

closes #10407

Kudos to @phi-bre for suggesting this in #16148 (comment)

[changeset-bot]

🦋 Changeset detected

Latest commit: 799451d

The changes in this PR will be included in the next version bump.

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@sveltejs/kit	Major

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16189-svelte.vercel.app/

[adiguba]

Hello,

Two remarks.

• Did the resolve() will be correctly typed ?

For example if I have this params :

export const params = defineParams({
  details: v.picklist(['min', 'standard', 'max']);
});

I think this should be typed accordingly :

resolve('/info/[details=details]', { details: 'min' }); // OK
resolve('/info/[details=details]', { details: 'minimum' }); // Type Error

• It would be nice to have an optional format() method to complement parse().
  This method would be used by resolve() to build the URL

For example, if I have bigint as uid, and I want to use it as hexadecimal on the URL :

export const params = defineParams({
  uid: {
    // parse the uid as a hexa BigInt :
    parse: v.pipe(v.string(),v.transform((value) => BigInt(`0x${value}`)),
    // format the BigInt in hexa
    format: (value) => value.toString(16)
   }
});

[sacrosanctic]

Food for thought, param.ts in singular form.

Though prior art is mixed:

• /params/[matcher].ts
• env.ts
• routes
• hooks.ts

[sirkostya009]

this is better than what we currently got. one question though, will this feature be backported to kit v2 behind an experimental flag? docs dont mention anything about that

[dummdidumm]

no there are no plans to backport this at the moment

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 799451d:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/799451de227f726e4bc967125c2b980e693c6f90

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16189

[Rich-Harris]

param.ts in singular form.

that wouldn't really make sense. hooks, routes, params are all plural. env isn't, because it's describing the environment as a whole, rather than multiple environments

[vercel]

Additional Suggestion:

A throwing param matcher breaks client-side navigation (silent no-op / unhandled promise rejection) even though the server handles the same throw gracefully, creating a server/client asymmetry introduced by commit f5479de.

[dummdidumm]

Vercel is right, but I don't see a good way how we can sensibly handle this. We could fall back to a full page reload to get the better error message eventually that way.

// in function navigate(...)
	try {
		intent ??= await get_navigation_intent(url, false);
	} catch {
		// Likely a matcher threw unexpectedly. Fall back to the server to get a proper error page.
		return await native_navigation(url, replace_state);
	}

Anything more would mean polluting the whole navigation code for such an edge case and that is not worth it. It should never happen anyway.

[Rich-Harris]

couple of suggestions but LGTM