Fix for array keys not working.

index.js

@@ -30,7 +30,7 @@ const copyWith = (key, value) =>
 function parseKeysInto (keyDescriptions, keys) {
     keyDescriptions.forEach(each => {
         if (typeof each === 'number' || isMapKey(each)) keys.push(each);
-        else if (Array.isArray(each)) fillKeys(each);
+        else if (Array.isArray(each)) parseKeysInto(each, keys);
         else keys.push(...each.toString().split('.'));
     });
     return keys;