From 684f7f742aede30f3a60def8419e7d5db472901c Mon Sep 17 00:00:00 2001
From: "svelte-docs-bot[bot]"
<196124396+svelte-docs-bot[bot]@users.noreply.github.com>
Date: Tue, 7 Oct 2025 12:19:02 +0000
Subject: [PATCH] sync kit docs
---
.../20-core-concepts/60-remote-functions.md | 58 +++++++++++++++++++
.../docs/kit/98-reference/10-@sveltejs-kit.md | 26 ++++++++-
.../docs/kit/98-reference/20-$app-server.md | 14 ++++-
3 files changed, 92 insertions(+), 6 deletions(-)
diff --git a/apps/svelte.dev/content/docs/kit/20-core-concepts/60-remote-functions.md b/apps/svelte.dev/content/docs/kit/20-core-concepts/60-remote-functions.md
index f0e26ff52e..eb1e5f4a78 100644
--- a/apps/svelte.dev/content/docs/kit/20-core-concepts/60-remote-functions.md
+++ b/apps/svelte.dev/content/docs/kit/20-core-concepts/60-remote-functions.md
@@ -451,6 +451,43 @@ Alternatively, you could use `select` and `select multiple`:
> [!NOTE] As with unchecked `checkbox` inputs, if no selections are made then the data will be `undefined`. For this reason, the `languages` field uses `v.optional(v.array(...), [])` rather than just `v.array(...)`.
+### Programmatic validation
+
+In addition to declarative schema validation, you can programmatically mark fields as invalid inside the form handler using the `invalid` function. This is useful for cases where you can't know if something is valid until you try to perform some action:
+
+```js
+/// file: src/routes/shop/data.remote.js
+import * as v from 'valibot';
+import { form } from '$app/server';
+import * as db from '$lib/server/database';
+
+export const buyHotcakes = form(
+ v.object({
+ qty: v.pipe(
+ v.number(),
+ v.minValue(1, 'you must buy at least one hotcake')
+ )
+ }),
+ async (data, invalid) => {
+ try {
+ await db.buy(data.qty);
+ } catch (e) {
+ if (e.code === 'OUT_OF_STOCK') {
+ invalid(
+ invalid.qty(`we don't have enough hotcakes`)
+ );
+ }
+ }
+ }
+);
+```
+
+The `invalid` function works as both a function and a proxy:
+
+- Call `invalid(issue1, issue2, ...issueN)` to throw a validation error
+- If an issue is a `string`, it applies to the form as a whole (and will show up in `fields.allIssues()`)
+- Use `invalid.fieldName(message)` to create an issue for a specific field. Like `fields` this is type-safe and you can use regular property access syntax to create issues for deeply nested objects (e.g. `invalid.profile.email('Email already exists')` or `invalid.items[0].qty('Insufficient stock')`)
+
### Validation
If the submitted data doesn't pass the schema, the callback will not run. Instead, each invalid field's `issues()` method will return an array of `{ message: string }` objects, and the `aria-invalid` attribute (returned from `as(...)`) will be set to `true`:
@@ -756,6 +793,27 @@ await submit().updates(
The override will be applied immediately, and released when the submission completes (or fails).
+### Multiple instances of a form
+
+Some forms may be repeated as part of a list. In this case you can create separate instances of a form function via `for(id)` to achieve isolation.
+
+```svelte
+
+
+
+Todos
+
+{#each await getTodos() as todo}
+ {@const modify = modifyTodo.for(todo.id)}
+
+{/each}
+```
+
### buttonProps
By default, submitting a form will send a request to the URL indicated by the `