From 700b5c4ec036cec70ade9ea610568a53a24d30d7 Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 03:24:13 -0700
Subject: [PATCH 01/12] chore: reduce use of any types

---
 packages/kit/src/exports/vite/dev/index.js | 11 ++++----
 packages/kit/src/exports/vite/index.js     | 32 ++++++++++++++++------
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index 8371a81ba5b1..e6e493d5886c 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -68,7 +68,8 @@ export async function dev(vite, vite_config, svelte_config, get_remotes) {
 	async function loud_ssr_load_module(url) {
 		try {
 			return await vite.ssrLoadModule(url, { fixStacktrace: true });
-		} catch (/** @type {any} */ err) {
+		} catch (/** @type {unknown} */ e) {
+			const err = /** @type {import('rollup').RollupError} */ (e);
 			const msg = buildErrorMessage(err, [colors.red(`Internal server error: ${err.message}`)]);
 
 			if (!vite.config.logger.hasErrorLogged(err)) {
@@ -77,13 +78,13 @@ export async function dev(vite, vite_config, svelte_config, get_remotes) {
 
 			vite.ws.send({
 				type: 'error',
-				err: {
+				err: /** @type {import('vite').ErrorPayload['err']} */ ({
 					...err,
 					// these properties are non-enumerable and will
 					// not be serialized unless we explicitly include them
 					message: err.message,
-					stack: err.stack
-				}
+					stack: err.stack ?? ''
+				})
 			});
 
 			throw err;
@@ -204,7 +205,7 @@ export async function dev(vite, vite_config, svelte_config, get_remotes) {
 
 						if (node.universal) {
 							if (node.page_options?.ssr === false) {
-								result.universal = node.page_options;
+								result.universal = /** @type {import('types').UniversalNode} */ (node.page_options);
 							} else {
 								// TODO: explain why the file was loaded on the server if we fail to load it
 								const { module, module_node } = await resolve(node.universal);
diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index b448fc7bb3d1..48896dd59787 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -424,7 +424,10 @@ async function kit({ svelte_config }) {
 					];
 				}
 
-				warn_overridden_config(config, new_config);
+				warn_overridden_config(
+					/** @type {Record<string, unknown>} */ (config),
+					/** @type {Record<string, unknown>} */ (new_config)
+				);
 
 				return new_config;
 			}
@@ -997,7 +1000,10 @@ async function kit({ svelte_config }) {
 					};
 				}
 
-				warn_overridden_config(config, new_config);
+				warn_overridden_config(
+					/** @type {Record<string, unknown>} */ (config),
+					/** @type {Record<string, unknown>} */ (new_config)
+				);
 
 				return new_config;
 			}
@@ -1148,7 +1154,11 @@ async function kit({ svelte_config }) {
 					client_chunks = bundle.output;
 				} catch (e) {
 					const error =
-						e instanceof Error ? e : new Error(/** @type {any} */ (e).message ?? e ?? '<unknown>');
+						e instanceof Error
+							? e
+							: new Error(
+									/** @type {{ message?: string }} */ (e).message ?? String(e) ?? '<unknown>'
+								);
 
 					// without this, errors that occur during the secondary build
 					// will be logged twice
@@ -1421,8 +1431,8 @@ async function kit({ svelte_config }) {
 }
 
 /**
- * @param {Record<string, any>} config
- * @param {Record<string, any>} resolved_config
+ * @param {Record<string, unknown>} config
+ * @param {Record<string, unknown>} resolved_config
  */
 function warn_overridden_config(config, resolved_config) {
 	const overridden = find_overridden_config(config, resolved_config, enforced_config, '', []);
@@ -1436,8 +1446,8 @@ function warn_overridden_config(config, resolved_config) {
 }
 
 /**
- * @param {Record<string, any>} config
- * @param {Record<string, any>} resolved_config
+ * @param {Record<string, unknown>} config
+ * @param {Record<string, unknown>} resolved_config
  * @param {import('./types.js').EnforcedConfig} enforced_config
  * @param {string} path
  * @param {string[]} out used locally to compute the return value
@@ -1456,7 +1466,13 @@ function find_overridden_config(config, resolved_config, enforced_config, path,
 					out.push(path + key);
 				}
 			} else {
-				find_overridden_config(config[key], resolved_config[key], enforced, path + key + '.', out);
+				find_overridden_config(
+					/** @type {Record<string, unknown>} */ (config[key]),
+					/** @type {Record<string, unknown>} */ (resolved_config[key]),
+					enforced,
+					path + key + '.',
+					out
+				);
 			}
 		}
 	}

From 3d7a8f2845ef56f118b9991580e2fc1f4c81c110 Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 13:26:59 -0700
Subject: [PATCH 02/12] update type signature of warn_overridden_config

---
 packages/kit/src/exports/vite/index.js | 28 +++++++++++++-------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 48896dd59787..56804f605989 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -43,6 +43,8 @@ import { compact } from '../../utils/array.js';
 import { should_ignore, has_children } from './static_analysis/utils.js';
 import { treeshake_prerendered_remotes } from './build/remote.js';
 
+/** @import { UserConfig } from 'vite' */
+
 const cwd = posixify(process.cwd());
 
 /** @type {import('./types.js').EnforcedConfig} */
@@ -424,10 +426,7 @@ async function kit({ svelte_config }) {
 					];
 				}
 
-				warn_overridden_config(
-					/** @type {Record<string, unknown>} */ (config),
-					/** @type {Record<string, unknown>} */ (new_config)
-				);
+				warn_overridden_config(config, new_config);
 
 				return new_config;
 			}
@@ -1000,10 +999,7 @@ async function kit({ svelte_config }) {
 					};
 				}
 
-				warn_overridden_config(
-					/** @type {Record<string, unknown>} */ (config),
-					/** @type {Record<string, unknown>} */ (new_config)
-				);
+				warn_overridden_config(config, new_config);
 
 				return new_config;
 			}
@@ -1156,9 +1152,7 @@ async function kit({ svelte_config }) {
 					const error =
 						e instanceof Error
 							? e
-							: new Error(
-									/** @type {{ message?: string }} */ (e).message ?? String(e) ?? '<unknown>'
-								);
+							: new Error(/** @type {{ message?: string }} */ (e).message ?? '<unknown>');
 
 					// without this, errors that occur during the secondary build
 					// will be logged twice
@@ -1431,11 +1425,17 @@ async function kit({ svelte_config }) {
 }
 
 /**
- * @param {Record<string, unknown>} config
- * @param {Record<string, unknown>} resolved_config
+ * @param {UserConfig} config
+ * @param {UserConfig} resolved_config
  */
 function warn_overridden_config(config, resolved_config) {
-	const overridden = find_overridden_config(config, resolved_config, enforced_config, '', []);
+	const overridden = find_overridden_config(
+		/** @type {Record<string, unknown>} */ (config),
+		/** @type {Record<string, unknown>} */ (resolved_config),
+		enforced_config,
+		'',
+		[]
+	);
 
 	if (overridden.length > 0) {
 		console.error(

From fb49085a1db9dfd03336067314715b5ee90d44bd Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 13:41:56 -0700
Subject: [PATCH 03/12] simplify

---
 packages/kit/src/exports/vite/index.js | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 56804f605989..1529ea9205ea 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1430,8 +1430,8 @@ async function kit({ svelte_config }) {
  */
 function warn_overridden_config(config, resolved_config) {
 	const overridden = find_overridden_config(
-		/** @type {Record<string, unknown>} */ (config),
-		/** @type {Record<string, unknown>} */ (resolved_config),
+		/** @type {IndexableConfig} */ (config),
+		/** @type {IndexableConfig} */ (resolved_config),
 		enforced_config,
 		'',
 		[]
@@ -1446,8 +1446,9 @@ function warn_overridden_config(config, resolved_config) {
 }
 
 /**
- * @param {Record<string, unknown>} config
- * @param {Record<string, unknown>} resolved_config
+ * @typedef {{ [key: string]: IndexableConfig | undefined }} IndexableConfig
+ * @param {IndexableConfig | undefined} config
+ * @param {IndexableConfig | undefined} resolved_config
  * @param {import('./types.js').EnforcedConfig} enforced_config
  * @param {string} path
  * @param {string[]} out used locally to compute the return value
@@ -1466,13 +1467,7 @@ function find_overridden_config(config, resolved_config, enforced_config, path,
 					out.push(path + key);
 				}
 			} else {
-				find_overridden_config(
-					/** @type {Record<string, unknown>} */ (config[key]),
-					/** @type {Record<string, unknown>} */ (resolved_config[key]),
-					enforced,
-					path + key + '.',
-					out
-				);
+				find_overridden_config(config[key], resolved_config[key], enforced, path + key + '.', out);
 			}
 		}
 	}

From f4fa9eae7de2ec43f4b5526c0d7008403bf7a11c Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 13:50:48 -0700
Subject: [PATCH 04/12] fix

---
 packages/kit/src/exports/vite/index.js   | 9 ++++-----
 packages/kit/src/exports/vite/types.d.ts | 4 ++++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 1529ea9205ea..ae35b2aca8bf 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1430,8 +1430,8 @@ async function kit({ svelte_config }) {
  */
 function warn_overridden_config(config, resolved_config) {
 	const overridden = find_overridden_config(
-		/** @type {IndexableConfig} */ (config),
-		/** @type {IndexableConfig} */ (resolved_config),
+		/** @type {import('./types.js').IndexableConfig } */ (config),
+		/** @type {import('./types.js').IndexableConfig } */ (resolved_config),
 		enforced_config,
 		'',
 		[]
@@ -1446,9 +1446,8 @@ function warn_overridden_config(config, resolved_config) {
 }
 
 /**
- * @typedef {{ [key: string]: IndexableConfig | undefined }} IndexableConfig
- * @param {IndexableConfig | undefined} config
- * @param {IndexableConfig | undefined} resolved_config
+ * @param {import('./types.js').IndexableConfig | undefined} config
+ * @param {import('./types.js').IndexableConfig  | undefined} resolved_config
  * @param {import('./types.js').EnforcedConfig} enforced_config
  * @param {string} path
  * @param {string[]} out used locally to compute the return value
diff --git a/packages/kit/src/exports/vite/types.d.ts b/packages/kit/src/exports/vite/types.d.ts
index 900aa43541ea..639348ceeda7 100644
--- a/packages/kit/src/exports/vite/types.d.ts
+++ b/packages/kit/src/exports/vite/types.d.ts
@@ -1,3 +1,7 @@
 export interface EnforcedConfig {
 	[key: string]: EnforcedConfig | true;
 }
+
+export interface IndexableConfig {
+	[key: string]: IndexableConfig | undefined
+}

From 123b8b386edb58d45696057bdca96683680dc813 Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 14:00:49 -0700
Subject: [PATCH 05/12] import additional types

---
 packages/kit/src/exports/vite/index.js   | 42 +++++++++++++-----------
 packages/kit/src/exports/vite/types.d.ts |  2 +-
 2 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index ae35b2aca8bf..10b639c0160f 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -43,7 +43,11 @@ import { compact } from '../../utils/array.js';
 import { should_ignore, has_children } from './static_analysis/utils.js';
 import { treeshake_prerendered_remotes } from './build/remote.js';
 
-/** @import { UserConfig } from 'vite' */
+/**
+ * @import { Options } from '@sveltejs/vite-plugin-svelte'
+ * @import { PreprocessorGroup } from 'svelte/compiler'
+ * @import { ConfigEnv, Manifest, Plugin, ResolvedConfig, UserConfig, ViteDevServer } from 'vite'
+ */
 
 const cwd = posixify(process.cwd());
 
@@ -89,7 +93,7 @@ const options_regex = /(export\s+const\s+(prerender|csr|ssr|trailingSlash))\s*=/
 /** @type {Set<string>} */
 const warned = new Set();
 
-/** @type {import('svelte/compiler').PreprocessorGroup} */
+/** @type {PreprocessorGroup} */
 const warning_preprocessor = {
 	script: ({ content, filename }) => {
 		if (!filename) return;
@@ -132,12 +136,12 @@ const warning_preprocessor = {
 
 /**
  * Returns the SvelteKit Vite plugins.
- * @returns {Promise<import('vite').Plugin[]>}
+ * @returns {Promise<Plugin[]>}
  */
 export async function sveltekit() {
 	const svelte_config = await load_config();
 
-	/** @type {import('@sveltejs/vite-plugin-svelte').Options['preprocess']} */
+	/** @type {Options['preprocess']} */
 	let preprocess = svelte_config.preprocess;
 	if (Array.isArray(preprocess)) {
 		preprocess = [...preprocess, warning_preprocessor];
@@ -147,7 +151,7 @@ export async function sveltekit() {
 		preprocess = warning_preprocessor;
 	}
 
-	/** @type {import('@sveltejs/vite-plugin-svelte').Options} */
+	/** @type {Options} */
 	const vite_plugin_svelte_options = {
 		configFile: false,
 		extensions: svelte_config.extensions,
@@ -187,7 +191,7 @@ let build_metadata = undefined;
  * - https://rollupjs.org/guide/en/#output-generation-hooks
  *
  * @param {{ svelte_config: import('types').ValidatedConfig }} options
- * @return {Promise<import('vite').Plugin[]>}
+ * @return {Promise<Plugin[]>}
  */
 async function kit({ svelte_config }) {
 	/** @type {import('vite')} */
@@ -201,10 +205,10 @@ async function kit({ svelte_config }) {
 
 	const version_hash = hash(kit.version.name);
 
-	/** @type {import('vite').ResolvedConfig} */
+	/** @type {ResolvedConfig} */
 	let vite_config;
 
-	/** @type {import('vite').ConfigEnv} */
+	/** @type {ConfigEnv} */
 	let vite_config_env;
 
 	/** @type {boolean} */
@@ -216,7 +220,7 @@ async function kit({ svelte_config }) {
 	/** @type {() => Promise<void>} */
 	let finalise;
 
-	/** @type {import('vite').UserConfig} */
+	/** @type {UserConfig} */
 	let initial_config;
 
 	const service_worker_entry_file = resolve_entry(kit.files.serviceWorker);
@@ -236,7 +240,7 @@ async function kit({ svelte_config }) {
 	const sourcemapIgnoreList = /** @param {string} relative_path */ (relative_path) =>
 		relative_path.includes('node_modules') || relative_path.includes(kit.outDir);
 
-	/** @type {import('vite').Plugin} */
+	/** @type {Plugin} */
 	const plugin_setup = {
 		name: 'vite-plugin-sveltekit-setup',
 
@@ -270,7 +274,7 @@ async function kit({ svelte_config }) {
 				const generated = path.posix.join(kit.outDir, 'generated');
 
 				// dev and preview config can be shared
-				/** @type {import('vite').UserConfig} */
+				/** @type {UserConfig} */
 				const new_config = {
 					resolve: {
 						alias: [
@@ -440,7 +444,7 @@ async function kit({ svelte_config }) {
 		}
 	};
 
-	/** @type {import('vite').Plugin} */
+	/** @type {Plugin} */
 	const plugin_virtual_modules = {
 		name: 'vite-plugin-sveltekit-virtual-modules',
 
@@ -564,7 +568,7 @@ async function kit({ svelte_config }) {
 	/**
 	 * Ensures that client-side code can't accidentally import server-side code,
 	 * whether in `*.server.js` files, `$app/server`, `$lib/server`, or `$env/[static|dynamic]/private`
-	 * @type {import('vite').Plugin}
+	 * @type {Plugin}
 	 */
 	const plugin_guard = {
 		name: 'vite-plugin-sveltekit-guard',
@@ -671,7 +675,7 @@ async function kit({ svelte_config }) {
 		}
 	};
 
-	/** @type {import('vite').ViteDevServer} */
+	/** @type {ViteDevServer} */
 	let dev_server;
 
 	/** @type {Array<{ hash: string, file: string }>} */
@@ -683,7 +687,7 @@ async function kit({ svelte_config }) {
 	/** @type {Set<string>} Track which remote hashes have already been emitted */
 	const emitted_remote_hashes = new Set();
 
-	/** @type {import('vite').Plugin} */
+	/** @type {Plugin} */
 	const plugin_remote = {
 		name: 'vite-plugin-sveltekit-remote',
 
@@ -812,7 +816,7 @@ async function kit({ svelte_config }) {
 		}
 	};
 
-	/** @type {import('vite').Plugin} */
+	/** @type {Plugin} */
 	const plugin_compile = {
 		name: 'vite-plugin-sveltekit-compile',
 
@@ -824,7 +828,7 @@ async function kit({ svelte_config }) {
 			// avoids overwriting the base setting that's also set by Vitest
 			order: 'pre',
 			handler(config) {
-				/** @type {import('vite').UserConfig} */
+				/** @type {UserConfig} */
 				let new_config;
 
 				const kit_paths_base = kit.paths.base || '/';
@@ -1072,7 +1076,7 @@ async function kit({ svelte_config }) {
 				const verbose = vite_config.logLevel === 'info';
 				const log = logger({ verbose });
 
-				/** @type {import('vite').Manifest} */
+				/** @type {Manifest} */
 				const server_manifest = JSON.parse(read(`${out}/server/.vite/manifest.json`));
 
 				/** @type {import('types').BuildData} */
@@ -1198,7 +1202,7 @@ async function kit({ svelte_config }) {
 					}
 				}
 
-				/** @type {import('vite').Manifest} */
+				/** @type {Manifest} */
 				const client_manifest = JSON.parse(read(`${out}/client/.vite/manifest.json`));
 
 				/**
diff --git a/packages/kit/src/exports/vite/types.d.ts b/packages/kit/src/exports/vite/types.d.ts
index 639348ceeda7..6b8e26742a43 100644
--- a/packages/kit/src/exports/vite/types.d.ts
+++ b/packages/kit/src/exports/vite/types.d.ts
@@ -3,5 +3,5 @@ export interface EnforcedConfig {
 }
 
 export interface IndexableConfig {
-	[key: string]: IndexableConfig | undefined
+	[key: string]: IndexableConfig | undefined;
 }

From 321cd8e6136a68d051da8a2c862e3903ccfcb2df Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 14:07:21 -0700
Subject: [PATCH 06/12] generate types

---
 packages/kit/types/index.d.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/kit/types/index.d.ts b/packages/kit/types/index.d.ts
index d23a0a4b7380..2d75e5ab0ab7 100644
--- a/packages/kit/types/index.d.ts
+++ b/packages/kit/types/index.d.ts
@@ -2935,10 +2935,11 @@ declare module '@sveltejs/kit/node/polyfills' {
 }
 
 declare module '@sveltejs/kit/vite' {
+	import type { Plugin } from 'vite';
 	/**
 	 * Returns the SvelteKit Vite plugins.
 	 * */
-	export function sveltekit(): Promise<import("vite").Plugin[]>;
+	export function sveltekit(): Promise<Plugin[]>;
 
 	export {};
 }

From 0b3a2da0fcfb671cab80fe067ee0f9ebc0454ad7 Mon Sep 17 00:00:00 2001
From: Ben McCann <322311+benmccann@users.noreply.github.com>
Date: Mon, 6 Apr 2026 14:14:35 -0700
Subject: [PATCH 07/12] use error.name if available

---
 packages/kit/src/exports/vite/index.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 10b639c0160f..1d44204d6a77 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1156,7 +1156,11 @@ async function kit({ svelte_config }) {
 					const error =
 						e instanceof Error
 							? e
-							: new Error(/** @type {{ message?: string }} */ (e).message ?? '<unknown>');
+							: new Error(
+									/** @type {{ message?: string }} */ (e).message ??
+										/** @type {{ name?: string }} */ (e).name ??
+										'<unknown>'
+								);
 
 					// without this, errors that occur during the secondary build
 					// will be logged twice

From 17fcffc4a289e345752ba1f10f5fed1cffb493b0 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Tue, 7 Apr 2026 15:13:07 -0400
Subject: [PATCH 08/12] Apply suggestion from @Rich-Harris

---
 packages/kit/src/exports/vite/index.js | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 1d44204d6a77..182796c5fb22 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1154,13 +1154,7 @@ async function kit({ svelte_config }) {
 					client_chunks = bundle.output;
 				} catch (e) {
 					const error =
-						e instanceof Error
-							? e
-							: new Error(
-									/** @type {{ message?: string }} */ (e).message ??
-										/** @type {{ name?: string }} */ (e).name ??
-										'<unknown>'
-								);
+						e instanceof Error ? e : new Error(/** @type {any} */ (e).message ?? e ?? '<unknown>');
 
 					// without this, errors that occur during the secondary build
 					// will be logged twice

From 1bb2e37fe2b91bffd247da239cac67662907c19c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 7 Apr 2026 15:13:43 -0400
Subject: [PATCH 09/12] fix

---
 packages/kit/src/exports/vite/index.js | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 182796c5fb22..73ccf5621064 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1,3 +1,6 @@
+/** @import { Options } from '@sveltejs/vite-plugin-svelte' */
+/** @import { PreprocessorGroup } from 'svelte/compiler' */
+/** @import { ConfigEnv, Manifest, Plugin, ResolvedConfig, UserConfig, ViteDevServer } from 'vite' */
 import fs from 'node:fs';
 import path from 'node:path';
 import process from 'node:process';
@@ -43,12 +46,6 @@ import { compact } from '../../utils/array.js';
 import { should_ignore, has_children } from './static_analysis/utils.js';
 import { treeshake_prerendered_remotes } from './build/remote.js';
 
-/**
- * @import { Options } from '@sveltejs/vite-plugin-svelte'
- * @import { PreprocessorGroup } from 'svelte/compiler'
- * @import { ConfigEnv, Manifest, Plugin, ResolvedConfig, UserConfig, ViteDevServer } from 'vite'
- */
-
 const cwd = posixify(process.cwd());
 
 /** @type {import('./types.js').EnforcedConfig} */
@@ -194,7 +191,7 @@ let build_metadata = undefined;
  * @return {Promise<Plugin[]>}
  */
 async function kit({ svelte_config }) {
-	/** @type {import('vite')} */
+	/** @type {typeof import('vite')} */
 	const vite = await import_peer('vite');
 
 	// @ts-ignore `vite.rolldownVersion` only exists in `vite 8`

From afe3df065f1112e46a3bf4b3c6aba0c1f3d421af Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 7 Apr 2026 15:18:20 -0400
Subject: [PATCH 10/12] fixes

---
 packages/kit/src/exports/vite/dev/index.js | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index e6e493d5886c..db50fa0b212c 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -1,3 +1,5 @@
+/** @import { RequestEvent } from '@sveltejs/kit' */
+/** @import { PrerenderOption } from 'types' */
 import fs from 'node:fs';
 import path from 'node:path';
 import process from 'node:process';
@@ -34,13 +36,19 @@ const vite_css_query_regex = /(?:\?|&)(?:raw|url|inline)(?:&|$)/;
 export async function dev(vite, vite_config, svelte_config, get_remotes) {
 	installPolyfills();
 
+	/** @type {AsyncLocalStorage<{ event: RequestEvent, config: any, prerender: PrerenderOption }>} */
 	const async_local_storage = new AsyncLocalStorage();
 
 	globalThis.__SVELTEKIT_TRACK__ = (label) => {
 		const context = async_local_storage.getStore();
 		if (!context || context.prerender === true) return;
 
-		check_feature(context.event.route.id, context.config, label, svelte_config.kit.adapter);
+		check_feature(
+			/** @type {string} */ (context.event.route.id),
+			context.config,
+			label,
+			svelte_config.kit.adapter
+		);
 	};
 
 	const fetch = globalThis.fetch;
@@ -438,7 +446,7 @@ export async function dev(vite, vite_config, svelte_config, get_remotes) {
 	return () => {
 		const serve_static_middleware = vite.middlewares.stack.find(
 			(middleware) =>
-				/** @type {function} */ (middleware.handle).name === 'viteServeStaticMiddleware'
+				/** @type {Function} */ (middleware.handle).name === 'viteServeStaticMiddleware'
 		);
 
 		// Vite will give a 403 on URLs like /test, /static, and /package.json preventing us from

From 67448875973c5cdd29dae007e1e6d0c5667a8910 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 7 Apr 2026 15:19:02 -0400
Subject: [PATCH 11/12] tweaks

---
 packages/kit/src/exports/vite/dev/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index db50fa0b212c..ecada10f23d0 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -1,5 +1,5 @@
 /** @import { RequestEvent } from '@sveltejs/kit' */
-/** @import { PrerenderOption } from 'types' */
+/** @import { PrerenderOption, UniversalNode } from 'types' */
 import fs from 'node:fs';
 import path from 'node:path';
 import process from 'node:process';
@@ -213,7 +213,7 @@ export async function dev(vite, vite_config, svelte_config, get_remotes) {
 
 						if (node.universal) {
 							if (node.page_options?.ssr === false) {
-								result.universal = /** @type {import('types').UniversalNode} */ (node.page_options);
+								result.universal = /** @type {UniversalNode} */ (node.page_options);
 							} else {
 								// TODO: explain why the file was loaded on the server if we fail to load it
 								const { module, module_node } = await resolve(node.universal);

From acdfeff5f288eec0962100d40acc98f819cda880 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 7 Apr 2026 15:20:22 -0400
Subject: [PATCH 12/12] this was fine as it was

---
 packages/kit/src/exports/vite/index.js   | 12 +++---------
 packages/kit/src/exports/vite/types.d.ts |  4 ----
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 73ccf5621064..fe829e73e240 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -1428,13 +1428,7 @@ async function kit({ svelte_config }) {
  * @param {UserConfig} resolved_config
  */
 function warn_overridden_config(config, resolved_config) {
-	const overridden = find_overridden_config(
-		/** @type {import('./types.js').IndexableConfig } */ (config),
-		/** @type {import('./types.js').IndexableConfig } */ (resolved_config),
-		enforced_config,
-		'',
-		[]
-	);
+	const overridden = find_overridden_config(config, resolved_config, enforced_config, '', []);
 
 	if (overridden.length > 0) {
 		console.error(
@@ -1445,8 +1439,8 @@ function warn_overridden_config(config, resolved_config) {
 }
 
 /**
- * @param {import('./types.js').IndexableConfig | undefined} config
- * @param {import('./types.js').IndexableConfig  | undefined} resolved_config
+ * @param {Record<string, any>} config
+ * @param {Record<string, any>} resolved_config
  * @param {import('./types.js').EnforcedConfig} enforced_config
  * @param {string} path
  * @param {string[]} out used locally to compute the return value
diff --git a/packages/kit/src/exports/vite/types.d.ts b/packages/kit/src/exports/vite/types.d.ts
index 6b8e26742a43..900aa43541ea 100644
--- a/packages/kit/src/exports/vite/types.d.ts
+++ b/packages/kit/src/exports/vite/types.d.ts
@@ -1,7 +1,3 @@
 export interface EnforcedConfig {
 	[key: string]: EnforcedConfig | true;
 }
-
-export interface IndexableConfig {
-	[key: string]: IndexableConfig | undefined;
-}