diff --git a/package.json b/package.json
index 154381ecff..6833896e86 100644
--- a/package.json
+++ b/package.json
@@ -50,6 +50,7 @@
     "tslint-loader": "^3.5.3",
     "typescript": "~2.5.2",
     "webpack": "~3.5.6",
+    "webpack-sources": "1.0.1",
     "webpack-manifest-plugin": "^1.3.2"
   }
 }