diff --git a/extensions/typescript-language-features/src/features/bufferSyncSupport.ts b/extensions/typescript-language-features/src/features/bufferSyncSupport.ts
index b8db32733a2..c2faca72c50 100644
--- a/extensions/typescript-language-features/src/features/bufferSyncSupport.ts
+++ b/extensions/typescript-language-features/src/features/bufferSyncSupport.ts
@@ -4,15 +4,14 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as fs from 'fs';
-import { CancellationTokenSource, Disposable, TextDocument, TextDocumentChangeEvent, TextDocumentContentChangeEvent, Uri, workspace, EventEmitter } from 'vscode';
+import { CancellationTokenSource, Disposable, EventEmitter, TextDocument, TextDocumentChangeEvent, TextDocumentContentChangeEvent, Uri, workspace } from 'vscode';
 import * as Proto from '../protocol';
 import { ITypeScriptServiceClient } from '../typescriptService';
+import API from '../utils/api';
 import { Delayer } from '../utils/async';
 import { disposeAll } from '../utils/dispose';
 import * as languageModeIds from '../utils/languageModeIds';
-import API from '../utils/api';
-import { memoize } from '../utils/memoize';
-import { getTempFile } from '../utils/temp';
+import { ResourceMap } from './resourceMap';
 
 enum BufferKind {
 	TypeScript = 1,
@@ -115,84 +114,6 @@ class SyncedBuffer {
 	}
 }
 
-/**
- * Maps of file resources
- *
- * Attempts to handle correct mapping on both case sensitive and case in-sensitive
- * file systems.
- */
-class ResourceMap<T> {
-	private readonly _map = new Map<string, T>();
-
-	constructor(
-		private readonly _normalizePath: (resource: Uri) => string | null
-	) { }
-
-	public has(resource: Uri): boolean {
-		const file = this.toKey(resource);
-		return !!file && this._map.has(file);
-	}
-
-	public get(resource: Uri): T | undefined {
-		const file = this.toKey(resource);
-		return file ? this._map.get(file) : undefined;
-	}
-
-	public set(resource: Uri, value: T) {
-		const file = this.toKey(resource);
-		if (file) {
-			this._map.set(file, value);
-		}
-	}
-
-	public delete(resource: Uri): void {
-		const file = this.toKey(resource);
-		if (file) {
-			this._map.delete(file);
-		}
-	}
-
-	public get values(): Iterable<T> {
-		return this._map.values();
-	}
-
-	public get keys(): Iterable<string> {
-		return this._map.keys();
-	}
-
-	private toKey(resource: Uri): string | null {
-		const key = this._normalizePath(resource);
-		if (!key) {
-			return key;
-		}
-
-		return this.isCaseInsensitivePath(key) ? key.toLowerCase() : key;
-	}
-
-	private isCaseInsensitivePath(path: string) {
-		if (isWindowsPath(path)) {
-			return true;
-		}
-
-		return path[0] === '/' && this.onIsCaseInsenitiveFileSystem;
-	}
-
-	@memoize
-	private get onIsCaseInsenitiveFileSystem() {
-		if (process.platform === 'win32') {
-			return true;
-		}
-
-		if (process.platform !== 'darwin') {
-			return false;
-		}
-
-		const temp = getTempFile('typescript-case-check');
-		fs.writeFileSync(temp, '');
-		return fs.existsSync(temp.toUpperCase());
-	}
-}
-
 class SyncedBufferMap extends ResourceMap<SyncedBuffer> {
 
 	public getForPath(filePath: string): SyncedBuffer | undefined {
@@ -208,7 +129,6 @@ class SyncedBufferMap extends ResourceMap<SyncedBuffer> {
 	}
 }
 
-
 export default class BufferSyncSupport {
 
 	private readonly client: ITypeScriptServiceClient;
@@ -445,6 +365,6 @@ export default class BufferSyncSupport {
 	}
 }
 
-function isWindowsPath(path: string): boolean {
+export function isWindowsPath(path: string): boolean {
 	return /^[a-zA-Z]:\\/.test(path);
 }
diff --git a/extensions/typescript-language-features/src/features/resourceMap.ts b/extensions/typescript-language-features/src/features/resourceMap.ts
new file mode 100644
index 00000000000..22959a08b89
--- /dev/null
+++ b/extensions/typescript-language-features/src/features/resourceMap.ts
@@ -0,0 +1,84 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as fs from 'fs';
+import { Uri } from 'vscode';
+import { memoize } from '../utils/memoize';
+import { getTempFile } from '../utils/temp';
+import { isWindowsPath } from './bufferSyncSupport';
+
+/**
+ * Maps of file resources
+ *
+ * Attempts to handle correct mapping on both case sensitive and case in-sensitive
+ * file systems.
+ */
+export class ResourceMap<T> {
+	private readonly _map = new Map<string, T>();
+
+	constructor(
+		private readonly _normalizePath: (resource: Uri) => string | null
+	) { }
+
+	public has(resource: Uri): boolean {
+		const file = this.toKey(resource);
+		return !!file && this._map.has(file);
+	}
+
+	public get(resource: Uri): T | undefined {
+		const file = this.toKey(resource);
+		return file ? this._map.get(file) : undefined;
+	}
+
+	public set(resource: Uri, value: T) {
+		const file = this.toKey(resource);
+		if (file) {
+			this._map.set(file, value);
+		}
+	}
+
+	public delete(resource: Uri): void {
+		const file = this.toKey(resource);
+		if (file) {
+			this._map.delete(file);
+		}
+	}
+
+	public get values(): Iterable<T> {
+		return this._map.values();
+	}
+
+	public get keys(): Iterable<string> {
+		return this._map.keys();
+	}
+
+	private toKey(resource: Uri): string | null {
+		const key = this._normalizePath(resource);
+		if (!key) {
+			return key;
+		}
+		return this.isCaseInsensitivePath(key) ? key.toLowerCase() : key;
+	}
+
+	private isCaseInsensitivePath(path: string) {
+		if (isWindowsPath(path)) {
+			return true;
+		}
+		return path[0] === '/' && this.onIsCaseInsenitiveFileSystem;
+	}
+
+	@memoize
+	private get onIsCaseInsenitiveFileSystem() {
+		if (process.platform === 'win32') {
+			return true;
+		}
+		if (process.platform !== 'darwin') {
+			return false;
+		}
+		const temp = getTempFile('typescript-case-check');
+		fs.writeFileSync(temp, '');
+		return fs.existsSync(temp.toUpperCase());
+	}
+}
diff --git a/extensions/typescript-language-features/src/utils/dependentRegistration.ts b/extensions/typescript-language-features/src/utils/dependentRegistration.ts
index 88e0cf00b02..18a0a2d7421 100644
--- a/extensions/typescript-language-features/src/utils/dependentRegistration.ts
+++ b/extensions/typescript-language-features/src/utils/dependentRegistration.ts
@@ -5,8 +5,8 @@
 
 import * as vscode from 'vscode';
 import { ITypeScriptServiceClient } from '../typescriptService';
-import API from '../utils/api';
-import { disposeAll } from '../utils/dispose';
+import API from './api';
+import { disposeAll } from './dispose';
 
 class ConditionalRegistration {
 	private registration: vscode.Disposable | undefined = undefined;