sveltejs · teemingc · Apr 1, 2026 · Mar 23, 2026 · Mar 23, 2026 · Mar 24, 2026
diff --git a/.changeset/full-flies-turn.md b/.changeset/full-flies-turn.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+feat: support TypeScript 6.0
diff --git a/packages/adapter-auto/package.json b/packages/adapter-auto/package.json
@@ -42,7 +42,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "catalog:",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vitest": "catalog:"
 	},
 	"peerDependencies": {

diff --git a/packages/adapter-auto/tsconfig.json b/packages/adapter-auto/tsconfig.json
@@ -3,12 +3,10 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"baseUrl": "."
+		"types": ["node"]
 	},
 	"include": ["**/*.js"]
 }
diff --git a/packages/adapter-cloudflare/package.json b/packages/adapter-cloudflare/package.json
@@ -52,7 +52,7 @@
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "catalog:",
 		"esbuild": "catalog:",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vitest": "catalog:"
 	},
 	"peerDependencies": {

diff --git a/packages/adapter-cloudflare/test/apps/pages/tsconfig.json b/packages/adapter-cloudflare/test/apps/pages/tsconfig.json
@@ -7,7 +7,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	},
 	"extends": "./.svelte-kit/tsconfig.json"

diff --git a/packages/adapter-cloudflare/test/apps/workers/tsconfig.json b/packages/adapter-cloudflare/test/apps/workers/tsconfig.json
@@ -7,7 +7,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	},
 	"extends": "./.svelte-kit/tsconfig.json"

diff --git a/packages/adapter-cloudflare/tsconfig.json b/packages/adapter-cloudflare/tsconfig.json
@@ -3,18 +3,15 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]
 		},
 		// taken from the Cloudflare Workers TypeScript template https://github.com/cloudflare/workers-sdk/blob/main/packages/create-cloudflare/templates/hello-world/ts/tsconfig.json
 		"lib": ["es2021"],
-		"types": ["@cloudflare/workers-types"]
+		"types": ["node", "@cloudflare/workers-types"]
 	},
 	"include": [
 		"index.js",

diff --git a/packages/adapter-netlify/index.js b/packages/adapter-netlify/index.js
@@ -312,7 +312,9 @@ function get_netlify_config() {
 	try {
 		return /** @type {NetlifyConfig} */ (toml.parse(readFileSync('netlify.toml', 'utf-8')));
 	} catch (err) {
-		err.message = `Error parsing netlify.toml: ${err.message}`;
+		if (err instanceof Error) {
+			err.message = `Error parsing netlify.toml: ${err.message}`;
+		}
 		throw err;
 	}
 }

diff --git a/packages/adapter-netlify/package.json b/packages/adapter-netlify/package.json
@@ -59,7 +59,7 @@
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "catalog:",
 		"rollup": "^4.59.0",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vitest": "catalog:"
 	},
 	"peerDependencies": {

diff --git a/packages/adapter-netlify/src/serverless.js b/packages/adapter-netlify/src/serverless.js
@@ -1,4 +1,4 @@
-import './shims';
+import './shims.js';
 import { Server } from '0SERVER';
 import { createReadableStream } from '@sveltejs/kit/node';
 import process from 'node:process';

diff --git a/packages/adapter-netlify/test/apps/basic/tsconfig.json b/packages/adapter-netlify/test/apps/basic/tsconfig.json
@@ -7,7 +7,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	},
 	"extends": "./.svelte-kit/tsconfig.json"

diff --git a/packages/adapter-netlify/test/apps/edge/tsconfig.json b/packages/adapter-netlify/test/apps/edge/tsconfig.json
@@ -7,7 +7,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	},
 	"extends": "./.svelte-kit/tsconfig.json"

diff --git a/packages/adapter-netlify/test/apps/split/tsconfig.json b/packages/adapter-netlify/test/apps/split/tsconfig.json
@@ -7,7 +7,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	},
 	"extends": "./.svelte-kit/tsconfig.json"

diff --git a/packages/adapter-netlify/tsconfig.json b/packages/adapter-netlify/tsconfig.json
@@ -3,16 +3,13 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["*.js", "src/**/*.js", "internal.d.ts", "test/utils.js"]
 }
diff --git a/packages/adapter-node/internal.d.ts b/packages/adapter-node/internal.d.ts
@@ -18,3 +18,5 @@ declare module 'MANIFEST' {
 declare module 'SERVER' {
 	export { Server } from '@sveltejs/kit';
 }
+
+declare module 'SHIMS' {}
diff --git a/packages/adapter-node/package.json b/packages/adapter-node/package.json
@@ -47,7 +47,7 @@
 		"@types/node": "catalog:",
 		"polka": "catalog:",
 		"sirv": "^3.0.2",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vitest": "catalog:"
 	},
 	"dependencies": {

diff --git a/packages/adapter-node/tsconfig.json b/packages/adapter-node/tsconfig.json
@@ -3,16 +3,13 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
-		"allowSyntheticDefaultImports": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": [
 		"index.js",

diff --git a/packages/adapter-static/package.json b/packages/adapter-static/package.json
@@ -44,7 +44,7 @@
 		"@types/node": "catalog:",
 		"sirv": "^3.0.0",
 		"svelte": "catalog:",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vite": "catalog:"
 	},
 	"peerDependencies": {

diff --git a/packages/adapter-static/tsconfig.json b/packages/adapter-static/tsconfig.json
@@ -3,16 +3,13 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["index.js", "internal.d.ts", "test/utils.js"]
 }
diff --git a/packages/adapter-vercel/package.json b/packages/adapter-vercel/package.json
@@ -46,7 +46,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@types/node": "catalog:",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vitest": "catalog:"
 	},
 	"peerDependencies": {

diff --git a/packages/adapter-vercel/test/apps/basic/package.json b/packages/adapter-vercel/test/apps/basic/package.json
@@ -12,7 +12,7 @@
 		"@sveltejs/kit": "workspace:*",
 		"@sveltejs/vite-plugin-svelte": "catalog:",
 		"svelte": "catalog:",
-		"typescript": "^5.3.3",
+		"typescript": "catalog:",
 		"vite": "catalog:"
 	},
 	"type": "module"

diff --git a/packages/adapter-vercel/test/apps/basic/tsconfig.json b/packages/adapter-vercel/test/apps/basic/tsconfig.json
@@ -9,7 +9,6 @@
 		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"sourceMap": true,
-		"strict": true,
 		"moduleResolution": "bundler"
 	}
 }
diff --git a/packages/adapter-vercel/tsconfig.json b/packages/adapter-vercel/tsconfig.json
@@ -2,18 +2,14 @@
 	"compilerOptions": {
 		"allowJs": true,
 		"checkJs": true,
-		"strict": true,
 		"noEmit": true,
-		"noImplicitAny": true,
-		"strictNullChecks": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../kit/types/index"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["*.js", "files/**/*.js", "internal.d.ts", "test/**/*.js"]
 }
diff --git a/packages/amp/package.json b/packages/amp/package.json
@@ -35,7 +35,7 @@
 	},
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
-		"typescript": "^5.3.3"
+		"typescript": "catalog:"
 	},
 	"peerDependencies": {
 		"@sveltejs/kit": "^1.0.0 || ^2.0.0"

diff --git a/packages/amp/tsconfig.json b/packages/amp/tsconfig.json
@@ -3,10 +3,8 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"strict": true,
 		"target": "es2022",
 		"module": "node16",
-		"moduleResolution": "node16",
-		"allowSyntheticDefaultImports": true
+		"moduleResolution": "node16"
 	}
 }
diff --git a/packages/enhanced-img/package.json b/packages/enhanced-img/package.json
@@ -49,7 +49,7 @@
 		"@types/node": "catalog:",
 		"rollup": "^4.59.0",
 		"svelte": "catalog:",
-		"typescript": "^5.6.3",
+		"typescript": "catalog:",
 		"vite": "catalog:",
 		"vitest": "catalog:"
 	},

diff --git a/packages/enhanced-img/tsconfig.json b/packages/enhanced-img/tsconfig.json
@@ -3,17 +3,16 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"strict": true,
 		"target": "es2022",
 		"module": "node16",
 		"moduleResolution": "node16",
-		"allowSyntheticDefaultImports": true,
 		"paths": {
 			"types": ["./types/index"],
 			"types/*": ["./types/*"]
 		},
 		"noUnusedLocals": true,
-		"noUnusedParameters": true
+		"noUnusedParameters": true,
+		"types": ["node"]
 	},
 	"include": ["src/**/*", "types/**/*", "test/**/*"]
 }
diff --git a/packages/kit/package.json b/packages/kit/package.json
@@ -38,7 +38,7 @@
 		"@types/connect": "catalog:",
 		"@types/node": "catalog:",
 		"@types/set-cookie-parser": "catalog:",
-		"dts-buddy": "catalog:",
+		"dts-buddy": "^0.7.0",
 		"rollup": "^4.59.0",
 		"svelte": "catalog:",
 		"svelte-preprocess": "catalog:",
@@ -50,7 +50,7 @@
 		"@sveltejs/vite-plugin-svelte": "^3.0.0 || ^4.0.0-next.1 || ^5.0.0 || ^6.0.0-next.0 || ^7.0.0",
 		"@opentelemetry/api": "^1.0.0",
 		"svelte": "^4.0.0 || ^5.0.0-next.0",
-		"typescript": "^5.3.3",
+		"typescript": "^5.3.3 || ^6.0.0",
 		"vite": "^5.0.3 || ^6.0.0 || ^7.0.0-beta.0 || ^8.0.0"
 	},
 	"peerDependenciesMeta": {

diff --git a/packages/kit/src/core/sync/write_tsconfig.js b/packages/kit/src/core/sync/write_tsconfig.js
@@ -121,7 +121,8 @@ export function get_tsconfig(kit) {
 			moduleResolution: 'bundler',
 			module: 'esnext',
 			noEmit: true, // prevent tsconfig error "overwriting input files" - Vite handles the build and ignores this
-			target: 'esnext'
+			target: 'esnext',
+			types: ['node']
 		},
 		include: [...include],
 		exclude
@@ -165,6 +166,7 @@ function validate_user_config(cwd, out, config) {
 	if (extends_framework_config) {
 		const { paths, baseUrl } = options;
 
+		// TODO: baseUrl will be removed in TypeScript 7.0
 		if (baseUrl || paths) {
 			console.warn(
 				colors

diff --git a/packages/kit/src/core/sync/write_types/test/actions/tsconfig.json b/packages/kit/src/core/sync/write_types/test/actions/tsconfig.json
@@ -3,17 +3,15 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"strict": true,
 		"target": "es2022",
 		"module": "es2022",
 		"moduleResolution": "bundler",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../../../../../exports/public"],
 			"types": ["../../../../../types/internal"],
 			"$app/types": ["../../../../../types/ambient.d.ts"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["./**/*.js", "./**/*.ts", ".svelte-kit/non-ambient.d.ts"],
 	"exclude": ["..svelte-kit/**"]

diff --git a/packages/kit/src/core/sync/write_types/test/app-types/tsconfig.json b/packages/kit/src/core/sync/write_types/test/app-types/tsconfig.json
@@ -3,17 +3,15 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"strict": true,
 		"target": "es2022",
 		"module": "es2022",
 		"moduleResolution": "bundler",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../../../../../exports/public"],
 			"types": ["../../../../../types/internal"],
 			"$app/types": ["../../../../../types/ambient.d.ts"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["./**/*.js", "./**/*.ts", ".svelte-kit/non-ambient.d.ts"],
 	"exclude": ["..svelte-kit/**"]

diff --git a/packages/kit/src/core/sync/write_types/test/layout-advanced/tsconfig.json b/packages/kit/src/core/sync/write_types/test/layout-advanced/tsconfig.json
@@ -3,17 +3,15 @@
 		"allowJs": true,
 		"checkJs": true,
 		"noEmit": true,
-		"strict": true,
 		"target": "es2022",
 		"module": "es2022",
 		"moduleResolution": "bundler",
-		"allowSyntheticDefaultImports": true,
-		"baseUrl": ".",
 		"paths": {
 			"@sveltejs/kit": ["../../../../../exports/public"],
 			"types": ["../../../../../types/internal"],
 			"$app/types": ["../../../../../types/ambient.d.ts"]
-		}
+		},
+		"types": ["node"]
 	},
 	"include": ["./**/*.js", "./**/*.ts", ".svelte-kit/non-ambient.d.ts"],
 	"exclude": ["..svelte-kit/**"]