diff --git a/src/vs/workbench/parts/html/common/htmlInput.ts b/src/vs/workbench/parts/html/common/htmlInput.ts
index 8338d4fd5b6..7f20aa1588e 100644
--- a/src/vs/workbench/parts/html/common/htmlInput.ts
+++ b/src/vs/workbench/parts/html/common/htmlInput.ts
@@ -2,18 +2,16 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-'use strict';
 
 import URI from 'vs/base/common/uri';
 import { ResourceEditorInput } from 'vs/workbench/common/editor/resourceEditorInput';
 import { ITextModelService } from 'vs/editor/common/services/resolverService';
 import { IHashService } from 'vs/workbench/services/hash/common/hashService';
 
-
 export interface HtmlInputOptions {
-	allowScripts?: boolean;
-	allowSvgs?: boolean;
-	svgWhiteList?: string[];
+	readonly allowScripts?: boolean;
+	readonly allowSvgs?: boolean;
+	readonly svgWhiteList?: string[];
 }
 
 export function areHtmlInputOptionsEqual(left: HtmlInputOptions, right: HtmlInputOptions) {