diff --git a/extensions/css-language-features/client/src/browser/cssClientMain.ts b/extensions/css-language-features/client/src/browser/cssClientMain.ts
index 6522c786389..c89997ffaa0 100644
--- a/extensions/css-language-features/client/src/browser/cssClientMain.ts
+++ b/extensions/css-language-features/client/src/browser/cssClientMain.ts
@@ -8,13 +8,6 @@ import { BaseLanguageClient, LanguageClientOptions } from 'vscode-languageclient
 import { startClient, LanguageClientConstructor } from '../cssClient';
 import { LanguageClient } from 'vscode-languageclient/browser';
 
-declare const Worker: {
-	new(stringUrl: string): any;
-};
-declare const TextDecoder: {
-	new(encoding?: string): { decode(buffer: ArrayBuffer): string };
-};
-
 let client: BaseLanguageClient | undefined;
 
 // this method is called when vs code is activated
@@ -25,7 +18,7 @@ export async function activate(context: ExtensionContext) {
 		worker.postMessage({ i10lLocation: l10n.uri?.toString(false) ?? '' });
 
 		const newLanguageClient: LanguageClientConstructor = (id: string, name: string, clientOptions: LanguageClientOptions) => {
-			return new LanguageClient(id, name, clientOptions, worker);
+			return new LanguageClient(id, name, worker, clientOptions);
 		};
 
 		client = await startClient(context, newLanguageClient, { TextDecoder });
diff --git a/extensions/css-language-features/client/tsconfig.json b/extensions/css-language-features/client/tsconfig.json
index 573b24b4aa6..44b77895c10 100644
--- a/extensions/css-language-features/client/tsconfig.json
+++ b/extensions/css-language-features/client/tsconfig.json
@@ -1,7 +1,10 @@
 {
 	"extends": "../../tsconfig.base.json",
 	"compilerOptions": {
-		"outDir": "./out"
+		"outDir": "./out",
+		"lib": [
+			"webworker"
+		]
 	},
 	"include": [
 		"src/**/*",
diff --git a/extensions/html-language-features/client/src/browser/htmlClientMain.ts b/extensions/html-language-features/client/src/browser/htmlClientMain.ts
index 3f10e6d131f..06997d39fb0 100644
--- a/extensions/html-language-features/client/src/browser/htmlClientMain.ts
+++ b/extensions/html-language-features/client/src/browser/htmlClientMain.ts
@@ -8,13 +8,6 @@ import { LanguageClientOptions } from 'vscode-languageclient';
 import { startClient, LanguageClientConstructor, AsyncDisposable } from '../htmlClient';
 import { LanguageClient } from 'vscode-languageclient/browser';
 
-declare const Worker: {
-	new(stringUrl: string): any;
-};
-declare const TextDecoder: {
-	new(encoding?: string): { decode(buffer: ArrayBuffer): string };
-};
-
 let client: AsyncDisposable | undefined;
 
 // this method is called when vs code is activated
@@ -25,7 +18,7 @@ export async function activate(context: ExtensionContext) {
 		worker.postMessage({ i10lLocation: l10n.uri?.toString(false) ?? '' });
 
 		const newLanguageClient: LanguageClientConstructor = (id: string, name: string, clientOptions: LanguageClientOptions) => {
-			return new LanguageClient(id, name, clientOptions, worker);
+			return new LanguageClient(id, name, worker, clientOptions);
 		};
 
 		const timer = {
diff --git a/extensions/html-language-features/client/tsconfig.json b/extensions/html-language-features/client/tsconfig.json
index 8f5cef74fd3..349af163eea 100644
--- a/extensions/html-language-features/client/tsconfig.json
+++ b/extensions/html-language-features/client/tsconfig.json
@@ -1,7 +1,10 @@
 {
 	"extends": "../../tsconfig.base.json",
 	"compilerOptions": {
-		"outDir": "./out"
+		"outDir": "./out",
+		"lib": [
+			"webworker"
+		]
 	},
 	"include": [
 		"src/**/*",
diff --git a/extensions/json-language-features/client/src/browser/jsonClientMain.ts b/extensions/json-language-features/client/src/browser/jsonClientMain.ts
index f78f494d727..91ed937fe6f 100644
--- a/extensions/json-language-features/client/src/browser/jsonClientMain.ts
+++ b/extensions/json-language-features/client/src/browser/jsonClientMain.ts
@@ -8,12 +8,6 @@ import { LanguageClientOptions } from 'vscode-languageclient';
 import { startClient, LanguageClientConstructor, SchemaRequestService, AsyncDisposable, languageServerDescription } from '../jsonClient';
 import { LanguageClient } from 'vscode-languageclient/browser';
 
-declare const Worker: {
-	new(stringUrl: string): any;
-};
-
-declare function fetch(uri: string, options: any): any;
-
 let client: AsyncDisposable | undefined;
 
 // this method is called when vs code is activated
@@ -24,7 +18,7 @@ export async function activate(context: ExtensionContext) {
 		worker.postMessage({ i10lLocation: l10n.uri?.toString(false) ?? '' });
 
 		const newLanguageClient: LanguageClientConstructor = (id: string, name: string, clientOptions: LanguageClientOptions) => {
-			return new LanguageClient(id, name, clientOptions, worker);
+			return new LanguageClient(id, name, worker, clientOptions);
 		};
 
 		const schemaRequests: SchemaRequestService = {
diff --git a/extensions/json-language-features/client/tsconfig.json b/extensions/json-language-features/client/tsconfig.json
index aa51e4d0157..89e6a6c12b7 100644
--- a/extensions/json-language-features/client/tsconfig.json
+++ b/extensions/json-language-features/client/tsconfig.json
@@ -1,7 +1,10 @@
 {
 	"extends": "../../tsconfig.base.json",
 	"compilerOptions": {
-		"outDir": "./out"
+		"outDir": "./out",
+		"lib": [
+			"webworker"
+		]
 	},
 	"include": [
 		"src/**/*",