diff --git a/package.json b/package.json
index e4013c32a..c75ea62bf 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "debug": "~2.1.0",
     "graceful-fs": "^3.0.6",
     "image-size": "0.3.5",
+    "immutable": "^3.7.4",
     "joi": "~5.1.0",
     "jstransform": "11.0.1",
     "module-deps": "3.5.6",