breaking: remove buttonProps from experimental remote form functions (sveltejs#14622)

* breaking: remove `buttonProps` from experimental remote form functions

use e.g. `<button {...myForm.fields.action.as('submit', 'register')}>Register</button>` button instead

* fix

* error in dev on buttonProps access

* fix

* fix tests

* tweak

* regenerate

---------

Co-authored-by: Rich Harris <richard.a.harris@gmail.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>

Author: dummdidumm

.changeset/honest-actors-arrive.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': minor
+---
+
+breaking: remove `buttonProps` from experimental remote form functions; use e.g. `<button {...myForm.fields.action.as('submit', 'register')}>Register</button>` button instead

documentation/docs/20-core-concepts/60-remote-functions.md

@@ -818,37 +818,56 @@ Some forms may be repeated as part of a list. In this case you can create separa
 {/each}
 ```
 
-### buttonProps
+### Multiple submit buttons
 
-By default, submitting a form will send a request to the URL indicated by the `<form>` element's [`action`](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/form#attributes_for_form_submission) attribute, which in the case of a remote function is a property on the form object generated by SvelteKit.
+It's possible for a `<form>` to have multiple submit buttons. For example, you might have a single form that allows you to log in or register depending on which button was clicked.
 
-It's possible for a `<button>` inside the `<form>` to send the request to a _different_ URL, using the [`formaction`](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/button#formaction) attribute. For example, you might have a single form that allows you to log in or register depending on which button was clicked.
-
-This attribute exists on the `buttonProps` property of a form object:
+To accomplish this, add a field to your schema for the button value, and use `as('submit', value)` to bind it:
 
 ```svelte
 <!--- file: src/routes/login/+page.svelte --->
 <script>
-	import { login, register } from '$lib/auth.remote';
+	import { loginOrRegister } from '$lib/auth';
 </script>
 
-<form {...login}>
+<form {...loginOrRegister}>
 	<label>
 		Your username
-		<input {...login.fields.username.as('text')} />
+		<input {...loginOrRegister.fields.username.as('text')} />
 	</label>
 
 	<label>
 		Your password
-		<input {...login.fields._password.as('password')} />
+		<input {...loginOrRegister.fields._password.as('password')} />
 	</label>
 
-	<button>login</button>
-	<button {...register.buttonProps}>register</button>
+	<button {...loginOrRegister.fields.action.as('submit', 'login')}>login</button>
+	<button {...loginOrRegister.fields.action.as('submit', 'register')}>register</button>
 </form>
 ```
 
-Like the form object itself, `buttonProps` has an `enhance` method for customizing submission behaviour.
+In your form handler, you can check which button was clicked:
+
+```js
+/// file: $lib/auth.js
+import * as v from 'valibot';
+import { form } from '$app/server';
+
+export const loginOrRegister = form(
+	v.object({
+		username: v.string(),
+		_password: v.string(),
+		action: v.picklist(['login', 'register'])
+	}),
+	async ({ username, _password, action }) => {
+		if (action === 'login') {
+			// handle login
+		} else {
+			// handle registration
+		}
+	}
+);
+```
 
 ## command
 

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

@@ -2078,30 +2078,6 @@ export type RemoteForm<Input extends RemoteFormInput | void, Output> = {
 	get pending(): number;
 	/** Access form fields using object notation */
 	fields: RemoteFormFields<Input>;
-	/** Spread this onto a `<button>` or `<input type="submit">` */
-	buttonProps: {
-		type: 'submit';
-		formmethod: 'POST';
-		formaction: string;
-		onclick: (event: Event) => void;
-		/** Use the `enhance` method to influence what happens when the form is submitted. */
-		enhance(
-			callback: (opts: {
-				form: HTMLFormElement;
-				data: Input;
-				submit: () => Promise<void> & {
-					updates: (...queries: Array<RemoteQuery<any> | RemoteQueryOverride>) => Promise<void>;
-				};
-			}) => void | Promise<void>
-		): {
-			type: 'submit';
-			formmethod: 'POST';
-			formaction: string;
-			onclick: (event: Event) => void;
-		};
-		/** The number of pending submissions */
-		get pending(): number;
-	};
 };
 
 /**

packages/kit/src/runtime/app/server/remote/form.js

@@ -84,21 +84,6 @@ export function form(validate_or_fn, maybe_fn) {
 			}
 		});
 
-		const button_props = {
-			type: 'submit',
-			onclick: () => {}
-		};
-
-		Object.defineProperty(button_props, 'enhance', {
-			value: () => {
-				return { type: 'submit', formaction: instance.buttonProps.formaction, onclick: () => {} };
-			}
-		});
-
-		Object.defineProperty(instance, 'buttonProps', {
-			value: button_props
-		});
-
 		/** @type {RemoteInfo} */
 		const __ = {
 			type: 'form',
@@ -190,11 +175,6 @@ export function form(validate_or_fn, maybe_fn) {
 			enumerable: true
 		});
 
-		Object.defineProperty(button_props, 'formaction', {
-			get: () => `?/remote=${__.id}`,
-			enumerable: true
-		});
-
 		Object.defineProperty(instance, 'fields', {
 			get() {
 				const data = get_cache(__)?.[''];
@@ -222,6 +202,15 @@ export function form(validate_or_fn, maybe_fn) {
 		// TODO 3.0 remove
 		if (DEV) {
 			throw_on_old_property_access(instance);
+
+			Object.defineProperty(instance, 'buttonProps', {
+				get() {
+					throw new Error(
+						'`form.buttonProps` has been removed: Instead of `<button {...form.buttonProps}>, use `<button {...form.fields.action.as("submit", "value")}>`.' +
+							' See the PR for more info: https://github.com/sveltejs/kit/pull/14622'
+					);
+				}
+			});
 		}
 
 		Object.defineProperty(instance, 'result', {
@@ -239,11 +228,6 @@ export function form(validate_or_fn, maybe_fn) {
 			get: () => 0
 		});
 
-		// On the server, buttonProps.pending is always 0
-		Object.defineProperty(button_props, 'pending', {
-			get: () => 0
-		});
-
 		Object.defineProperty(instance, 'preflight', {
 			// preflight is a noop on the server
 			value: () => instance

packages/kit/src/runtime/client/remote-functions/form.svelte.js

@@ -425,74 +425,23 @@ export function form(id) {
 			)
 		);
 
-		/** @param {Parameters<RemoteForm<any, any>['buttonProps']['enhance']>[0]} callback */
-		const form_action_onclick = (callback) => {
-			/** @param {Event} event */
-			return async (event) => {
-				const target = /** @type {HTMLButtonElement} */ (event.currentTarget);
-				const form = target.form;
-				if (!form) return;
-
-				// Prevent this from firing the form's submit event
-				event.stopPropagation();
-				event.preventDefault();
-
-				const form_data = new FormData(form, target);
-
-				if (DEV) {
-					const enctype = target.hasAttribute('formenctype')
-						? target.formEnctype
-						: clone(form).enctype;
-
-					validate_form_data(form_data, enctype);
-				}
-
-				await handle_submit(form, form_data, callback);
-			};
-		};
-
-		/** @type {RemoteForm<any, any>['buttonProps']} */
-		// @ts-expect-error we gotta set enhance as a non-enumerable property
-		const button_props = {
-			type: 'submit',
-			formmethod: 'POST',
-			formaction: action,
-			onclick: form_action_onclick(({ submit, form }) =>
-				submit().then(() => {
-					if (!issues.$) {
-						form.reset();
-					}
-				})
-			)
-		};
-
-		Object.defineProperty(button_props, 'enhance', {
-			/** @type {RemoteForm<any, any>['buttonProps']['enhance']} */
-			value: (callback) => {
-				return {
-					type: 'submit',
-					formmethod: 'POST',
-					formaction: action,
-					onclick: form_action_onclick(callback)
-				};
-			}
-		});
-
-		Object.defineProperty(button_props, 'pending', {
-			get: () => pending_count
-		});
-
 		let validate_id = 0;
 
 		// TODO 3.0 remove
 		if (DEV) {
 			throw_on_old_property_access(instance);
+
+			Object.defineProperty(instance, 'buttonProps', {
+				get() {
+					throw new Error(
+						'`form.buttonProps` has been removed: Instead of `<button {...form.buttonProps}>, use `<button {...form.fields.action.as("submit", "value")}>`.' +
+							' See the PR for more info: https://github.com/sveltejs/kit/pull/14622'
+					);
+				}
+			});
 		}
 
 		Object.defineProperties(instance, {
-			buttonProps: {
-				value: button_props
-			},
 			fields: {
 				get: () =>
 					create_field_proxy(

packages/kit/test/apps/async/src/routes/remote/form/[test_name]/+page.svelte

@@ -1,10 +1,5 @@
 <script>
-	import {
-		get_message,
-		set_message,
-		resolve_deferreds,
-		set_reverse_message
-	} from './form.remote.js';
+	import { get_message, set_message, resolve_deferreds } from './form.remote.js';
 
 	const { params } = $props();
 
@@ -27,19 +22,14 @@
 
 	<input {...set_message.fields.message.as('text')} />
 	<input {...set_message.fields.test_name.as('hidden', params.test_name)} />
-	<!--
-	 NOTE: there really probably should be a `set_reverse_message' test_name hidden field here, but it collides with the one above.
-	 This kind of lines up with our discussions from earlier where we were talking about needing to include the RF hash in the field name.
-	 If we do that and this test starts failing, all we'll need to do is add the hidden field back in.
-	-->
-	<button>set message</button>
-	<button {...set_reverse_message.buttonProps}>set reverse message</button>
+
+	<button {...set_message.fields.action.as('submit', 'normal')}>set message</button>
+	<button {...set_message.fields.action.as('submit', 'reverse')}>set reverse message</button>
 </form>
 
 <p>set_message.input.message: {set_message.fields.message.value()}</p>
 <p>set_message.pending: {set_message.pending}</p>
 <p>set_message.result: {set_message.result}</p>
-<p>set_reverse_message.result: {set_reverse_message.result}</p>
 
 <hr />
 

packages/kit/test/apps/async/src/routes/remote/form/[test_name]/form.remote.ts

@@ -16,10 +16,11 @@ export const set_message = form(
 		test_name: v.string(),
 		id: v.optional(v.string()),
 		message: v.picklist(
-			['hello', 'goodbye', 'unexpected error', 'expected error', 'redirect'],
+			['hello', 'goodbye', 'unexpected error', 'expected error', 'redirect', 'backwards'],
 			'message is invalid'
 		),
-		uppercase: v.optional(v.string())
+		uppercase: v.optional(v.string()),
+		action: v.optional(v.picklist(['normal', 'reverse']))
 	}),
 	async (data) => {
 		if (data.message === 'unexpected error') {
@@ -37,7 +38,11 @@ export const set_message = form(
 		const instance = instances.get(data.test_name) ?? { message: 'initial', deferreds: [] };
 		instances.set(data.test_name, instance);
 
-		instance.message = data.uppercase === 'true' ? data.message.toUpperCase() : data.message;
+		if (data.action === 'reverse') {
+			instance.message = data.message.split('').reverse().join('');
+		} else {
+			instance.message = data.uppercase === 'true' ? data.message.toUpperCase() : data.message;
+		}
 
 		if (getRequestEvent().isRemoteRequest) {
 			const deferred = Promise.withResolvers<void>();

packages/kit/test/apps/async/test/test.js

@@ -135,22 +135,21 @@ test.describe('remote functions', () => {
 		await page.waitForURL('/remote');
 	});
 
-	test('form.buttonProps works', async ({ page, javaScriptEnabled }) => {
-		await page.goto('/remote/form/button-props');
+	test('form multiple submit buttons work', async ({ page, javaScriptEnabled }) => {
+		await page.goto('/remote/form/multiple-submit');
 
 		await page.fill('[data-unscoped] input', 'backwards');
 		await page.getByText('set reverse message').click();
 
 		if (javaScriptEnabled) {
+			await page.getByText('resolve deferreds').click();
 			await page.getByText('message.current: sdrawkcab').waitFor();
 			await expect(page.getByText('await get_message():')).toHaveText(
 				'await get_message(): sdrawkcab'
 			);
 		}
 
-		await expect(page.getByText('set_reverse_message.result')).toHaveText(
-			'set_reverse_message.result: sdrawkcab'
-		);
+		await expect(page.getByText('set_message.result')).toHaveText('set_message.result: sdrawkcab');
 	});
 
 	test('form scoping with for(...) works', async ({ page, javaScriptEnabled }) => {

packages/kit/types/index.d.ts

@@ -2054,30 +2054,6 @@ declare module '@sveltejs/kit' {
 		get pending(): number;
 		/** Access form fields using object notation */
 		fields: RemoteFormFields<Input>;
-		/** Spread this onto a `<button>` or `<input type="submit">` */
-		buttonProps: {
-			type: 'submit';
-			formmethod: 'POST';
-			formaction: string;
-			onclick: (event: Event) => void;
-			/** Use the `enhance` method to influence what happens when the form is submitted. */
-			enhance(
-				callback: (opts: {
-					form: HTMLFormElement;
-					data: Input;
-					submit: () => Promise<void> & {
-						updates: (...queries: Array<RemoteQuery<any> | RemoteQueryOverride>) => Promise<void>;
-					};
-				}) => void | Promise<void>
-			): {
-				type: 'submit';
-				formmethod: 'POST';
-				formaction: string;
-				onclick: (event: Event) => void;
-			};
-			/** The number of pending submissions */
-			get pending(): number;
-		};
 	};
 
 	/**