fix: require a value with submit and hidden fields

.changeset/pink-ghosts-see.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: require a value with `submit` and `hidden` fields

packages/kit/src/exports/public.d.ts

@@ -1850,19 +1850,23 @@ export type RemoteFormFieldType<T> = {
 // Input element properties based on type
 type InputElementProps<T extends keyof InputTypeMap> = T extends 'checkbox' | 'radio'
 	? {
+			name: string;
 			type: T;
+			value?: string;
 			'aria-invalid': boolean | 'false' | 'true' | undefined;
 			get checked(): boolean;
 			set checked(value: boolean);
 		}
 	: T extends 'file'
 		? {
+				name: string;
 				type: 'file';
 				'aria-invalid': boolean | 'false' | 'true' | undefined;
 				get files(): FileList | null;
 				set files(v: FileList | null);
 			}
 		: {
+				name: string;
 				type: T;
 				'aria-invalid': boolean | 'false' | 'true' | undefined;
 				get value(): string | number;
@@ -1882,10 +1886,10 @@ export type RemoteFormFieldValue = string | string[] | number | boolean | File |
 
 type AsArgs<Type extends keyof InputTypeMap, Value> = Type extends 'checkbox'
 	? Value extends string[]
-		? [type: 'checkbox', value: Value[number] | (string & {})]
+		? [type: Type, value: Value[number] | (string & {})]
 		: [type: Type]
-	: Type extends 'radio'
-		? [type: 'radio', value: Value | (string & {})]
+	: Type extends 'radio' | 'submit' | 'hidden'
+		? [type: Type, value: Value | (string & {})]
 		: [type: Type];
 
 /**

packages/kit/src/runtime/form-utils.svelte.js

@@ -266,6 +266,19 @@ export function create_field_proxy(target, get_input, set_input, get_issues, pat
 						base_props.type = type === 'file multiple' ? 'file' : type;
 					}
 
+					// Handle submit and hidden inputs
+					if (type === 'submit' || type === 'hidden') {
+						if (DEV) {
+							if (!input_value) {
+								throw new Error(`\`${type}\` inputs must have a value`);
+							}
+						}
+
+						return Object.defineProperties(base_props, {
+							value: { value: input_value, enumerable: true }
+						});
+					}
+
 					// Handle select inputs
 					if (type === 'select' || type === 'select multiple') {
 						return Object.defineProperties(base_props, {

packages/kit/test/apps/basics/src/routes/remote/form/submitter/+page.svelte

@@ -3,7 +3,7 @@
 </script>
 
 <form {...my_form}>
-	<button {...my_form.fields.submitter.as('submit')} value="hello">submit</button>
+	<button {...my_form.fields.submitter.as('submit', 'hello')}>submit</button>
 </form>
 
 <p id="result">{my_form.result}</p>

packages/kit/test/apps/basics/src/routes/remote/form/validate/+page.svelte

@@ -26,7 +26,7 @@
 
 	<button>submit (imperative validation)</button>
 
-	<button bind:this={submitter} {...my_form.fields.button.as('submit')} value="incorrect_value">
+	<button bind:this={submitter} {...my_form.fields.button.as('submit', 'incorrect_value')}>
 		submit
 	</button>
 	{#each my_form.fields.button.issues() as issue}

packages/kit/types/index.d.ts

@@ -1826,19 +1826,23 @@ declare module '@sveltejs/kit' {
 	// Input element properties based on type
 	type InputElementProps<T extends keyof InputTypeMap> = T extends 'checkbox' | 'radio'
 		? {
+				name: string;
 				type: T;
+				value?: string;
 				'aria-invalid': boolean | 'false' | 'true' | undefined;
 				get checked(): boolean;
 				set checked(value: boolean);
 			}
 		: T extends 'file'
 			? {
+					name: string;
 					type: 'file';
 					'aria-invalid': boolean | 'false' | 'true' | undefined;
 					get files(): FileList | null;
 					set files(v: FileList | null);
 				}
 			: {
+					name: string;
 					type: T;
 					'aria-invalid': boolean | 'false' | 'true' | undefined;
 					get value(): string | number;
@@ -1858,10 +1862,10 @@ declare module '@sveltejs/kit' {
 
 	type AsArgs<Type extends keyof InputTypeMap, Value> = Type extends 'checkbox'
 		? Value extends string[]
-			? [type: 'checkbox', value: Value[number] | (string & {})]
+			? [type: Type, value: Value[number] | (string & {})]
 			: [type: Type]
-		: Type extends 'radio'
-			? [type: 'radio', value: Value | (string & {})]
+		: Type extends 'radio' | 'submit' | 'hidden'
+			? [type: Type, value: Value | (string & {})]
 			: [type: Type];
 
 	/**