diff --git a/extensions/typescript-language-features/src/utils/platform.ts b/extensions/typescript-language-features/src/utils/platform.ts
index 3e8f08c9f04..bb4e7cdbfd9 100644
--- a/extensions/typescript-language-features/src/utils/platform.ts
+++ b/extensions/typescript-language-features/src/utils/platform.ts
@@ -10,7 +10,7 @@ export function isWeb(): boolean {
 }
 
 export function isWebAndHasSharedArrayBuffers(): boolean {
-	return isWeb() && globalThis['crossOriginIsolated'];
+	return isWeb() && !!(globalThis as Record<string, unknown>)['crossOriginIsolated'];
 }
 
 export function supportsReadableByteStreams(): boolean {