diff --git a/extensions/typescript/src/features/bufferSyncSupport.ts b/extensions/typescript/src/features/bufferSyncSupport.ts
index 05dbefb4a1a..64c8eea9a40 100644
--- a/extensions/typescript/src/features/bufferSyncSupport.ts
+++ b/extensions/typescript/src/features/bufferSyncSupport.ts
@@ -106,7 +106,7 @@ export default class BufferSyncSupport {
 	private readonly disposables: Disposable[] = [];
 	private readonly syncedBuffers: Map<string, SyncedBuffer>;
 
-	private pendingDiagnostics: { [key: string]: number; };
+	private pendingDiagnostics = new Map<string, number>();
 	private readonly diagnosticDelayer: Delayer<any>;
 	private checkGlobalTSCVersion: boolean;
 
@@ -116,7 +116,6 @@ export default class BufferSyncSupport {
 		this.diagnostics = diagnostics;
 		this._validate = validate;
 
-		this.pendingDiagnostics = Object.create(null);
 		this.diagnosticDelayer = new Delayer<any>(300);
 
 		this.syncedBuffers = new Map<string, SyncedBuffer>();
@@ -211,7 +210,7 @@ export default class BufferSyncSupport {
 			return;
 		}
 		for (const filePath of this.syncedBuffers.keys()) {
-			this.pendingDiagnostics[filePath] = Date.now();
+			this.pendingDiagnostics.set(filePath, Date.now());
 		}
 		this.diagnosticDelayer.trigger(() => {
 			this.sendPendingDiagnostics();
@@ -223,7 +222,7 @@ export default class BufferSyncSupport {
 			return;
 		}
 
-		this.pendingDiagnostics[file] = Date.now();
+		this.pendingDiagnostics.set(file, Date.now());
 		const buffer = this.syncedBuffers.get(file);
 		let delay = 300;
 		if (buffer) {
@@ -239,10 +238,10 @@ export default class BufferSyncSupport {
 		if (!this._validate) {
 			return;
 		}
-		let files = Object.keys(this.pendingDiagnostics).map((key) => {
+		let files = Array.from(this.pendingDiagnostics.entries()).map(([key, value]) => {
 			return {
 				file: key,
-				time: this.pendingDiagnostics[key]
+				time: value
 			};
 		}).sort((a, b) => {
 			return a.time - b.time;
@@ -252,7 +251,7 @@ export default class BufferSyncSupport {
 
 		// Add all open TS buffers to the geterr request. They might be visible
 		for (const file of this.syncedBuffers.keys()) {
-			if (!this.pendingDiagnostics[file]) {
+			if (!this.pendingDiagnostics.get(file)) {
 				files.push(file);
 			}
 		}
@@ -264,7 +263,7 @@ export default class BufferSyncSupport {
 			};
 			this.client.execute('geterr', args, false);
 		}
-		this.pendingDiagnostics = Object.create(null);
+		this.pendingDiagnostics.clear();
 	}
 
 	private checkTSCVersion() {