diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 254fc434f64..f180bc83ad3 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -690,7 +690,7 @@ namespace ts {
     }
 
     function ConvertJsonOptionToStringArray(optionName: string, optionJson: any, errors: Diagnostic[], func?: (element: string) => string): string[] {
-        let items: string[] = [];
+        const items: string[] = [];
         let invalidOptionType = false;
         if (!isArray(optionJson)) {
             invalidOptionType = true;