diff --git a/lib/mergeWithProps.js b/lib/mergeWithProps.js
index <HASH>..<HASH> 100644
--- a/lib/mergeWithProps.js
+++ b/lib/mergeWithProps.js
@@ -23,7 +23,7 @@ export default function(json, props = {}) {
             json.mix = [ json.mix ];
         }
 
-        json.mix.concat(props.mix);
+        json.mix = json.mix.concat(props.mix);
     }
 
     return json;
:heavy_check_mark: merging mix with props fix