fixes #18

modules/objectMergeDeep.js

@@ -1,18 +1,23 @@
 export default function objectMergeDeep(base = {}, ...objs) {
   for (let i = 0, len = objs.length; i < len; ++i) {
-    const obj = objs[i]
+    const obj = objs[i];
 
     for (const key in obj) {
-      const value = obj[key]
+      // see https://github.com/robinweser/fast-loops/issues/18
+      if (key === '__proto__' || key === 'constructor' || key === 'prototype') {
+        continue;
+      }
+
+      const value = obj[key];
 
-      if (typeof value === 'object' && !Array.isArray(value)) {
-        base[key] = objectMergeDeep(base[key], value)
-        continue
+      if (typeof value === 'object' && !Array.isArray(value) && value !== null) {
+        base[key] = objectMergeDeep(base[key], value);
+        continue;
       }
 
-      base[key] = value
+      base[key] = value;
     }
   }
 
-  return base
-}
+  return base;
+}