From 84b9ebd0d7c40b9987f2ee8c7b821ac550eb5b2a Mon Sep 17 00:00:00 2001
From: Kanchalai Tanglertsampan <yuisu@microsoft.com>
Date: Wed, 22 Feb 2017 15:42:22 -0800
Subject: [PATCH] Return empty string instead to prevent exception downstream
 particularly in writeReferencePath

---
 src/compiler/utilities.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 66bf693d831d6..528544e46d09d 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -2653,7 +2653,7 @@ namespace ts {
             if (sourceFiles.length) {
                 const jsFilePath = options.outFile || options.out;
                 const sourceMapFilePath = getSourceMapFilePath(jsFilePath, options);
-                const declarationFilePath = options.declaration ? removeFileExtension(jsFilePath) + ".d.ts" : undefined;
+                const declarationFilePath = options.declaration ? removeFileExtension(jsFilePath) + ".d.ts" : "";
                 action({ jsFilePath, sourceMapFilePath, declarationFilePath }, createBundle(sourceFiles), emitOnlyDtsFiles);
             }
         }