diff --git a/src/services/shims.ts b/src/services/shims.ts
index a233f99d03f..e8b9b59b3cd 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -61,7 +61,7 @@ namespace ts {
         getLocalizedDiagnosticMessages(): string;
         getCancellationToken(): HostCancellationToken;
         getCurrentDirectory(): string;
-        getDirectories(path: string): string[];
+        getDirectories(path: string): string;
         getDefaultLibFileName(options: string): string;
         getNewLine?(): string;
         getProjectVersion?(): string;
@@ -404,7 +404,7 @@ namespace ts {
         }
 
         public getDirectories(path: string): string[] {
-            return this.shimHost.getDirectories(path);
+            return JSON.parse(this.shimHost.getDirectories(path));
         }
 
         public getDefaultLibFileName(options: CompilerOptions): string {