diff --git a/extensions/typescript/src/extension.ts b/extensions/typescript/src/extension.ts
index 2c015f82f2f39d29dd8b6fcd0a715361b3ec1b15..364e154bb1536557f8e5704d878e7b6e8dd9709f 100644
--- a/extensions/typescript/src/extension.ts
+++ b/extensions/typescript/src/extension.ts
@@ -16,7 +16,7 @@ import * as languageConfigurations from './utils/languageConfigurations';
 import { standardLanguageDescriptions } from './utils/languageDescription';
 import ManagedFileContextManager from './utils/managedFileContext';
 import { lazy, Lazy } from './utils/lazy';
-import TypeScriptServiceClient from './typescriptServiceClient';
+import * as fileSchemes from './utils/fileSchemes';
 
 export function activate(
 	context: vscode.ExtensionContext
@@ -94,10 +94,5 @@ function isSupportedDocument(
 	if (supportedLanguage.indexOf(document.languageId) < 0) {
 		return false;
 	}
-	const scheme = document.uri.scheme;
-	return (
-		scheme === TypeScriptServiceClient.WALK_THROUGH_SNIPPET_SCHEME
-		|| scheme === 'untitled'
-		|| scheme === 'file'
-	);
+	return fileSchemes.isSupportedScheme(document.uri.scheme);
 }
\ No newline at end of file
diff --git a/extensions/typescript/src/typescriptServiceClient.ts b/extensions/typescript/src/typescriptServiceClient.ts
index 8d584a0e3aec5096757fc6cd525a684d0d73448d..89964180240cf987b3442cf6c87509bfea013c2a 100644
--- a/extensions/typescript/src/typescriptServiceClient.ts
+++ b/extensions/typescript/src/typescriptServiceClient.ts
@@ -26,6 +26,8 @@ import * as nls from 'vscode-nls';
 import { TypeScriptServiceConfiguration, TsServerLogLevel } from './utils/configuration';
 import { TypeScriptVersionProvider, TypeScriptVersion } from './utils/versionProvider';
 import { TypeScriptVersionPicker } from './utils/versionPicker';
+import * as fileSchemes from './utils/fileSchemes';
+
 const localize = nls.loadMessageBundle();
 
 interface CallbackItem {
@@ -107,8 +109,7 @@ class RequestQueue {
 }
 
 export default class TypeScriptServiceClient implements ITypeScriptServiceClient {
-	public static readonly WALK_THROUGH_SNIPPET_SCHEME = 'walkThroughSnippet';
-	private static readonly WALK_THROUGH_SNIPPET_SCHEME_COLON = `${TypeScriptServiceClient.WALK_THROUGH_SNIPPET_SCHEME}:`;
+	private static readonly WALK_THROUGH_SNIPPET_SCHEME_COLON = `${fileSchemes.walkThroughSnippet}:`;
 
 	private pathSeparator: string;
 
@@ -555,15 +556,15 @@ export default class TypeScriptServiceClient implements ITypeScriptServiceClient
 	}
 
 	public normalizePath(resource: Uri): string | null {
-		if (resource.scheme === TypeScriptServiceClient.WALK_THROUGH_SNIPPET_SCHEME) {
+		if (resource.scheme === fileSchemes.walkThroughSnippet) {
 			return resource.toString();
 		}
 
-		if (resource.scheme === 'untitled' && this._apiVersion.has213Features()) {
+		if (resource.scheme === fileSchemes.untitled && this._apiVersion.has213Features()) {
 			return resource.toString();
 		}
 
-		if (resource.scheme !== 'file') {
+		if (resource.scheme !== fileSchemes.file) {
 			return null;
 		}
 		const result = resource.fsPath;
@@ -576,7 +577,7 @@ export default class TypeScriptServiceClient implements ITypeScriptServiceClient
 
 	public asUrl(filepath: string): Uri {
 		if (filepath.startsWith(TypeScriptServiceClient.WALK_THROUGH_SNIPPET_SCHEME_COLON)
-			|| (filepath.startsWith('untitled:') && this._apiVersion.has213Features())
+			|| (filepath.startsWith(fileSchemes.untitled + ':') && this._apiVersion.has213Features())
 		) {
 			return Uri.parse(filepath);
 		}
@@ -589,7 +590,7 @@ export default class TypeScriptServiceClient implements ITypeScriptServiceClient
 			return undefined;
 		}
 
-		if (resource.scheme === 'file' || resource.scheme === 'untitled') {
+		if (resource.scheme === fileSchemes.file || resource.scheme === fileSchemes.untitled) {
 			for (const root of roots.sort((a, b) => a.uri.fsPath.length - b.uri.fsPath.length)) {
 				if (resource.fsPath.startsWith(root.uri.fsPath + path.sep)) {
 					return root.uri.fsPath;
diff --git a/extensions/typescript/src/utils/fileSchemes.ts b/extensions/typescript/src/utils/fileSchemes.ts
new file mode 100644
index 0000000000000000000000000000000000000000..285ea43f33177d8c5ceb2821fb42d860256b48a2
--- /dev/null
+++ b/extensions/typescript/src/utils/fileSchemes.ts
@@ -0,0 +1,20 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+export const file = 'file';
+
+export const untitled = 'untitled';
+
+export const walkThroughSnippet = 'walkThroughSnippet';
+
+export const supportedSchemes = [
+	file,
+	untitled,
+	walkThroughSnippet
+];
+
+export function isSupportedScheme(scheme: string): boolean {
+	return supportedSchemes.indexOf(scheme) >= 0;
+}
\ No newline at end of file