breaking: upgrade to TypeScript 5

.changeset/silent-mayflies-burn.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': major
+---
+
+breaking: upgrade to TypeScript 5 and default `moduleResolution` to `bundler` in user projects

package.json

@@ -31,7 +31,7 @@
 		"playwright": "1.30.0",
 		"prettier": "^3.1.0",
 		"svelte": "^4.2.7",
-		"typescript": "^4.9.4"
+		"typescript": "^5.3.2"
 	},
 	"packageManager": "[email protected]",
 	"engines": {

packages/adapter-auto/package.json

@@ -32,7 +32,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "^16.18.6",
-		"typescript": "^4.9.4"
+		"typescript": "^5.3.2"
 	},
 	"dependencies": {
 		"import-meta-resolve": "^4.0.0"

packages/adapter-cloudflare-workers/package.json

@@ -37,7 +37,7 @@
 	"devDependencies": {
 		"@cloudflare/kv-asset-handler": "^0.3.0",
 		"@types/node": "^16.18.6",
-		"typescript": "^4.9.4"
+		"typescript": "^5.3.2"
 	},
 	"peerDependencies": {
 		"@sveltejs/kit": "^1.0.0"

packages/adapter-cloudflare/package.json

@@ -39,7 +39,7 @@
 	"devDependencies": {
 		"@types/node": "^16.18.6",
 		"@types/ws": "^8.5.3",
-		"typescript": "^4.9.4"
+		"typescript": "^5.3.2"
 	},
 	"peerDependencies": {
 		"@sveltejs/kit": "^1.0.0"

packages/adapter-netlify/package.json

@@ -38,15 +38,15 @@
 		"set-cookie-parser": "^2.6.0"
 	},
 	"devDependencies": {
-		"@netlify/functions": "^2.0.1",
+		"@netlify/functions": "^2.4.0",
 		"@rollup/plugin-commonjs": "^25.0.7",
 		"@rollup/plugin-json": "^6.0.1",
 		"@rollup/plugin-node-resolve": "^15.2.3",
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "^16.18.6",
 		"@types/set-cookie-parser": "^2.4.2",
 		"rollup": "^4.2.0",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vitest": "^0.34.5"
 	},
 	"peerDependencies": {

packages/adapter-netlify/rollup.config.js

@@ -12,6 +12,7 @@ const config = {
 		dir: 'files/esm',
 		format: 'esm'
 	},
+	// @ts-ignore https://github.com/rollup/plugins/issues/1329
 	plugins: [nodeResolve({ preferBuiltins: true }), commonjs(), json()],
 	external: (id) => id === '0SERVER' || id.startsWith('node:'),
 	preserveEntrySignatures: 'exports-only'

packages/adapter-netlify/tsconfig.json

@@ -5,10 +5,10 @@
 		"noEmit": true,
 		"noImplicitAny": true,
 		"target": "es2022",
-		"module": "es2022",
-		// `@netlify/function` > `@netlify/serverless-functions-api` types are not compatible,
-		// so using this moduleResolution for now
-		"moduleResolution": "node",
+		"module": "node16",
+		"moduleResolution": "node16",
+		// https://github.com/netlify/functions/issues/447
+		"skipLibCheck": true,
 		"allowSyntheticDefaultImports": true,
 		"baseUrl": ".",
 		"paths": {

packages/adapter-node/index.js

@@ -62,7 +62,9 @@ export default function (opts = {}) {
 						preferBuiltins: true,
 						exportConditions: ['node']
 					}),
+					// @ts-ignore https://github.com/rollup/plugins/issues/1329
 					commonjs({ strictRequires: true }),
+					// @ts-ignore https://github.com/rollup/plugins/issues/1329
 					json()
 				]
 			});

packages/adapter-node/package.json

@@ -39,7 +39,7 @@
 		"c8": "^8.0.0",
 		"polka": "^1.0.0-next.23",
 		"sirv": "^2.0.3",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vitest": "^0.34.5"
 	},
 	"dependencies": {

packages/adapter-node/src/index.js

@@ -6,6 +6,7 @@ export const path = env('SOCKET_PATH', false);
 export const host = env('HOST', '0.0.0.0');
 export const port = env('PORT', !path && '3000');
 
+// @ts-ignore - https://github.com/lukeed/polka/issues/199
 const server = polka().use(handler);
 
 server.listen({ path, host, port }, () => {

packages/adapter-node/tsconfig.json

@@ -6,11 +6,8 @@
 		"noImplicitAny": true,
 		"allowSyntheticDefaultImports": true,
 		"target": "es2022",
-		"module": "es2022",
-		// Can't use moduleResolution: node16 because of these issues:
-		// https://github.com/rollup/plugins/issues/1329
-		// https://github.com/lukeed/polka/issues/199
-		"moduleResolution": "node",
+		"module": "node16",
+		"moduleResolution": "node16",
 		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]

packages/adapter-static/index.js

@@ -52,6 +52,7 @@ See https://kit.svelte.dev/docs/page-options#prerender for more details`
 			}
 
 			const {
+				// @ts-ignore
 				pages = 'build',
 				assets = pages,
 				fallback,

packages/adapter-static/package.json

@@ -35,7 +35,7 @@
 		"@types/node": "^16.18.6",
 		"sirv": "^2.0.3",
 		"svelte": "^4.2.7",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vite": "^5.0.4"
 	},
 	"peerDependencies": {

packages/adapter-vercel/package.json

@@ -37,7 +37,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "^16.18.6",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vitest": "^0.34.5"
 	},
 	"peerDependencies": {

packages/create-svelte/templates/default/package.json

@@ -12,7 +12,7 @@
 		"@sveltejs/adapter-auto": "workspace:*",
 		"@sveltejs/kit": "workspace:*",
 		"svelte": "^4.2.7",
-		"typescript": "^5.0.0",
+		"typescript": "^5.3.2",
 		"vite": "^5.0.4"
 	},
 	"type": "module",

packages/create-svelte/templates/skeletonlib/package.template.json

@@ -25,7 +25,7 @@
 		"publint": "^0.1.9",
 		"svelte": "^4.2.7",
 		"tslib": "^2.4.1",
-		"typescript": "^5.0.0",
+		"typescript": "^5.3.2",
 		"vite": "^5.0.3"
 	},
 	"svelte": "./dist/index.js",

packages/enhanced-img/package.json

@@ -28,14 +28,15 @@
 	"dependencies": {
 		"magic-string": "^0.30.0",
 		"svelte-parse-markup": "^0.1.1",
-		"vite-imagetools": "^6.2.5"
+		"vite-imagetools": "^6.2.6"
 	},
 	"devDependencies": {
 		"@types/estree": "^1.0.2",
 		"@types/node": "^16.18.6",
 		"estree-walker": "^3.0.3",
+		"rollup": "^4.2.0",
 		"svelte": "^4.2.7",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vite": "^5.0.4",
 		"vitest": "^0.34.0"
 	}

packages/enhanced-img/tsconfig.json

@@ -5,8 +5,8 @@
 		"noEmit": true,
 		"strict": true,
 		"target": "es2022",
-		"module": "es2022",
-		"moduleResolution": "node",
+		"module": "node16",
+		"moduleResolution": "node16",
 		"allowSyntheticDefaultImports": true,
 		"paths": {
 			"types": ["./types/index"],

packages/kit/package.json

@@ -31,11 +31,11 @@
 		"@types/node": "^16.18.6",
 		"@types/sade": "^1.7.4",
 		"@types/set-cookie-parser": "^2.4.2",
-		"dts-buddy": "^0.2.4",
+		"dts-buddy": "^0.4.0",
 		"rollup": "^4.2.0",
 		"svelte": "^4.2.7",
 		"svelte-preprocess": "^5.1.1",
-		"typescript": "^4.9.4",
+		"typescript": "^5.3.2",
 		"vite": "^5.0.4",
 		"vitest": "^0.34.5"
 	},

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

@@ -139,7 +139,7 @@ export function get_tsconfig(kit, include_base_url) {
 			// This is required for svelte-package to work as expected
 			// Can be overwritten
 			lib: ['esnext', 'DOM', 'DOM.Iterable'],
-			moduleResolution: 'node', // TODO change to "bundler" in SvelteKit v2
+			moduleResolution: 'bundler',
 			module: 'esnext',
 			noEmit: true, // prevent tsconfig error "overwriting input files" - Vite handles the build and ignores this
 			target: 'esnext',

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

@@ -65,6 +65,7 @@ test('Allows generated tsconfig to be mutated', () => {
 
 	const config = get_tsconfig(kit, false);
 
+	// @ts-expect-error
 	assert.equal(config.extends, 'some/other/tsconfig.json');
 });
 
@@ -82,6 +83,7 @@ test('Allows generated tsconfig to be replaced', () => {
 
 	const config = get_tsconfig(kit, false);
 
+	// @ts-expect-error
 	assert.equal(config.extends, 'some/other/tsconfig.json');
 });
 

packages/kit/src/core/sync/write_types/test/package.json

@@ -1,5 +1,6 @@
 {
 	"private": true,
+	"type": "module",
 	"scripts": {
 		"testtypes": "tsc"
 	}

packages/kit/src/core/sync/write_types/test/tsconfig.json

@@ -4,9 +4,9 @@
 		"checkJs": true,
 		"noEmit": true,
 		"strict": true,
-		"target": "es2020",
+		"target": "es2022",
 		"module": "es2022",
-		"moduleResolution": "node",
+		"moduleResolution": "bundler",
 		"allowSyntheticDefaultImports": true,
 		"baseUrl": ".",
 		"paths": {

packages/kit/src/exports/vite/index.js

@@ -78,7 +78,7 @@ const options_regex = /(export\s+const\s+(prerender|csr|ssr|trailingSlash))\s*=/
 /** @type {Set<string>} */
 const warned = new Set();
 
-/** @type {import('@sveltejs/vite-plugin-svelte').PreprocessorGroup} */
+/** @type {import('svelte/compiler').PreprocessorGroup} */
 const warning_preprocessor = {
 	script: ({ content, filename }) => {
 		if (!filename) return;
@@ -630,7 +630,7 @@ function kit({ svelte_config }) {
 				scoped(
 					assets,
 					sirv(join(svelte_config.kit.outDir, 'output/client'), {
-					setHeaders: (res, pathname) => {
+						setHeaders: (res, pathname) => {
 							// only apply to immutable directory, not e.g. version.json
 							if (pathname.startsWith(`/${svelte_config.kit.appDir}/immutable`)) {
 								res.setHeader('cache-control', 'public,max-age=31536000,immutable');

packages/kit/src/exports/vite/preview/index.js

@@ -60,69 +60,67 @@ export async function preview(vite, vite_config, svelte_config) {
 
 		// prerendered pages (we can't just use sirv because we need to
 		// preserve the correct trailingSlash behaviour)
-		vite.middlewares.use(
-			(req, res, next) => {
-				let if_none_match_value = req.headers['if-none-match'];
+		vite.middlewares.use((req, res, next) => {
+			let if_none_match_value = req.headers['if-none-match'];
 
-				if (if_none_match_value?.startsWith('W/"')) {
-					if_none_match_value = if_none_match_value.substring(2);
-				}
+			if (if_none_match_value?.startsWith('W/"')) {
+				if_none_match_value = if_none_match_value.substring(2);
+			}
 
-				if (if_none_match_value === etag) {
-					res.statusCode = 304;
-					res.end();
-					return;
-				}
+			if (if_none_match_value === etag) {
+				res.statusCode = 304;
+				res.end();
+				return;
+			}
 
-				const { pathname, search } = new URL(/** @type {string} */ (req.url), 'http://dummy');
-
-				let filename = normalizePath(
-					join(svelte_config.kit.outDir, 'output/prerendered/pages' + pathname)
-				);
-				let prerendered = is_file(filename);
-
-				if (!prerendered) {
-					const has_trailing_slash = pathname.endsWith('/');
-					const html_filename = `${filename}${has_trailing_slash ? 'index.html' : '.html'}`;
-
-					/** @type {string | undefined} */
-					let redirect;
-
-					if (is_file(html_filename)) {
-						filename = html_filename;
-						prerendered = true;
-					} else if (has_trailing_slash) {
-						if (is_file(filename.slice(0, -1) + '.html')) {
-							redirect = pathname.slice(0, -1);
-						}
-					} else if (is_file(filename + '/index.html')) {
-						redirect = pathname + '/';
-					}
+			const { pathname, search } = new URL(/** @type {string} */ (req.url), 'http://dummy');
+
+			let filename = normalizePath(
+				join(svelte_config.kit.outDir, 'output/prerendered/pages' + pathname)
+			);
+			let prerendered = is_file(filename);
 
-					if (redirect) {
-						if (search) redirect += search;
-						res.writeHead(307, {
-							location: redirect
-						});
+			if (!prerendered) {
+				const has_trailing_slash = pathname.endsWith('/');
+				const html_filename = `${filename}${has_trailing_slash ? 'index.html' : '.html'}`;
 
-						res.end();
+				/** @type {string | undefined} */
+				let redirect;
 
-						return;
+				if (is_file(html_filename)) {
+					filename = html_filename;
+					prerendered = true;
+				} else if (has_trailing_slash) {
+					if (is_file(filename.slice(0, -1) + '.html')) {
+						redirect = pathname.slice(0, -1);
 					}
+				} else if (is_file(filename + '/index.html')) {
+					redirect = pathname + '/';
 				}
 
-				if (prerendered) {
-					res.writeHead(200, {
-						'content-type': lookup(pathname) || 'text/html',
-						etag
+				if (redirect) {
+					if (search) redirect += search;
+					res.writeHead(307, {
+						location: redirect
 					});
 
-					fs.createReadStream(filename).pipe(res);
-				} else {
-					next();
+					res.end();
+
+					return;
 				}
 			}
-		);
+
+			if (prerendered) {
+				res.writeHead(200, {
+					'content-type': lookup(pathname) || 'text/html',
+					etag
+				});
+
+				fs.createReadStream(filename).pipe(res);
+			} else {
+				next();
+			}
+		});
 
 		// SSR
 		vite.middlewares.use(async (req, res) => {