Merge pull request #612 from affinity/moberegger/optimize-_map_collection

Author: rafaelfranca

lib/jbuilder.rb

@@ -356,9 +356,11 @@ def _set_value(key, value)
   end
 
   def _map_collection(collection)
-    collection.map do |element|
+    collection = collection.map do |element|
       _scope{ yield element }
-    end - [BLANK]
+    end
+    collection.delete(BLANK)
+    collection
   end
 
   def _scope