feat: provide SvelteKit html typings (#11222)

This makes it possible to delete these from svelte/elements in Svelte 5 and have them controled in SvelteKit, decoupling the two
closes #10534

Author: dummdidumm

.changeset/smart-buttons-return.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': minor
+---
+
+feat: provide SvelteKit html typings

packages/kit/src/core/sync/sync.js

@@ -5,6 +5,7 @@ import { write_root } from './write_root.js';
 import { write_tsconfig } from './write_tsconfig.js';
 import { write_types, write_all_types } from './write_types/index.js';
 import { write_ambient } from './write_ambient.js';
+import { write_non_ambient } from './write_non_ambient.js';
 import { write_server } from './write_server.js';
 
 /**
@@ -15,6 +16,7 @@ import { write_server } from './write_server.js';
 export function init(config, mode) {
 	write_tsconfig(config.kit);
 	write_ambient(config.kit, mode);
+	write_non_ambient(config.kit);
 }
 
 /**

packages/kit/src/core/sync/write_non_ambient.js

@@ -0,0 +1,42 @@
+import path from 'node:path';
+import { GENERATED_COMMENT } from '../../constants.js';
+import { write_if_changed } from './utils.js';
+
+// `declare module "svelte/elements"` needs to happen in a non-ambient module, and dts-buddy generates one big ambient module,
+// so we can't add it there - therefore generate the typings ourselves here.
+// We're not using the `declare namespace svelteHTML` variant because that one doesn't augment the HTMLAttributes interface
+// people could use to type their own components.
+// The T generic is needed or else there's a "all declarations must have identical type parameters" error.
+const template = `
+${GENERATED_COMMENT}
+
+declare module "svelte/elements" {
+	export interface HTMLAttributes<T> {
+		'data-sveltekit-keepfocus'?: true | '' | 'off' | undefined | null;
+		'data-sveltekit-noscroll'?: true | '' | 'off' | undefined | null;
+		'data-sveltekit-preload-code'?:
+			| true
+			| ''
+			| 'eager'
+			| 'viewport'
+			| 'hover'
+			| 'tap'
+			| 'off'
+			| undefined
+			| null;
+		'data-sveltekit-preload-data'?: true | '' | 'hover' | 'tap' | 'off' | undefined | null;
+		'data-sveltekit-reload'?: true | '' | 'off' | undefined | null;
+		'data-sveltekit-replacestate'?: true | '' | 'off' | undefined | null;
+	}
+}
+
+export {};
+`;
+
+/**
+ * Writes non-ambient declarations to the output directory
+ * @param {import('types').ValidatedKitConfig} config
+ */
+export function write_non_ambient(config) {
+	write_if_changed(path.join(config.outDir, 'non-ambient.d.ts'), template);
+}

packages/kit/src/core/sync/write_tsconfig.js

@@ -86,6 +86,7 @@ export function get_tsconfig(kit, include_base_url) {
 
 	const include = new Set([
 		'ambient.d.ts',
+		'non-ambient.d.ts',
 		'./types/**/$types.d.ts',
 		config_relative('vite.config.js'),
 		config_relative('vite.config.ts')
@@ -109,7 +110,7 @@ export function get_tsconfig(kit, include_base_url) {
 	include.add(config_relative(`${test_folder}/**/*.ts`));
 	include.add(config_relative(`${test_folder}/**/*.svelte`));
 
-	const exclude = [config_relative('node_modules/**'), './[!ambient.d.ts]**'];
+	const exclude = [config_relative('node_modules/**')];
 	if (path.extname(kit.files.serviceWorker)) {
 		exclude.push(config_relative(kit.files.serviceWorker));
 	} else {

packages/kit/src/core/sync/write_tsconfig.spec.js

@@ -100,6 +100,7 @@ test('Creates tsconfig include from kit.files', () => {
 
 	expect(include).toEqual([
 		'ambient.d.ts',
+		'non-ambient.d.ts',
 		'./types/**/$types.d.ts',
 		'../vite.config.js',
 		'../vite.config.ts',