Code should be compatible with Node 4.5.0

assets/build/.eslintrc

@@ -2,6 +2,7 @@
   "root": false,
   "extends": "airbnb",
   "rules": {
-    "import/no-extraneous-dependencies": 0
+    "import/no-extraneous-dependencies": 0,
+    "prefer-rest-params": 0
   }
 }

assets/build/util/mergeWithConcat.js

@@ -2,9 +2,13 @@
 
 const mergeWith = require('lodash/mergeWith');
 
-module.exports = (...args) => mergeWith(...args, (a, b) => {
-  if (Array.isArray(a) && Array.isArray(b)) {
-    return a.concat(b);
-  }
-  return undefined;
-});
+module.exports = function mergeWithConcat() {
+  const args = [].slice.call(arguments);
+  args.push((a, b) => {
+    if (Array.isArray(a) && Array.isArray(b)) {
+      return a.concat(b);
+    }
+    return undefined;
+  });
+  return mergeWith.apply(this, args);
+};

assets/build/webpack.config.js

@@ -175,6 +175,8 @@ const webpackConfig = {
   ],
 };
 
+module.exports = webpackConfig;
+
 if (config.env.production) {
   module.exports = mergeWithConcat(webpackConfig, webpackConfigProduction);
 }