dateProxy fix for snapshots

Author: ciscoheat

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed diff algorithm problem with tainted objects.
 - Prevented crash when custom validity doesn't exist for an element.
+- `dateProxy` didn't restore properly with [snapshots](https://superforms.rocks/concepts/snapshots).
 
 ### Changed
 

src/lib/client/proxies.ts

@@ -350,7 +350,9 @@ function _stringProxy<T extends Record<string, unknown>, Path extends FormPaths<
 			if (typeof value === 'number' && isNaN(value)) return '';
 			return String(value);
 		} else if (type == 'date') {
-			const date = value as unknown as Date;
+			const date =
+				typeof value === 'string' || typeof value === 'number' ? new Date(value) : (value as Date);
+
 			if (isNaN(date as unknown as number)) return '';
 
 			switch (options.dateFormat) {

src/routes/(v2)/v2/issue-562/+page.server.ts

@@ -0,0 +1,15 @@
+import { Schema } from './schemas.js';
+import { superValidate } from '$lib/index.js';
+import { valibot } from '$lib/adapters/valibot.js';
+
+export const load = async () => {
+	const initialData = {
+		date: new Date()
+	};
+
+	const form = await superValidate(initialData, valibot(Schema));
+
+	return {
+		form
+	};
+};

src/routes/(v2)/v2/issue-562/+page.svelte

@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { Schema } from './schemas.js';
+	import { valibotClient } from '$lib/adapters/valibot.js';
+	import { dateProxy, superForm } from '$lib/client/index.js';
+
+	let { data } = $props();
+
+	const { form, capture, restore } = superForm(data.form, {
+		validators: valibotClient(Schema)
+	});
+
+	const proxy = dateProxy(form, 'date', {
+		format: 'datetime-local',
+		empty: 'undefined'
+	});
+
+	// works without this, fails with it when refreshing page, not when from another page
+	export const snapshot = { capture, restore };
+
+	$inspect({ $form, $proxy });
+</script>
+
+<input type="datetime-local" bind:value={$proxy} />

src/routes/(v2)/v2/issue-562/schemas.ts

@@ -0,0 +1,5 @@
+import * as v from 'valibot';
+
+export const Schema = v.object({
+	date: v.date()
+});