Enhance performance

Author: abrisse

lib/json/ld/flatten.rb

@@ -255,9 +255,9 @@ def rename_bnodes(node)
         when Array
           node.map { |n| rename_bnodes(n) }
         when Hash
-          node.inject({}) do |memo, (k, v)|
+          node.each_with_object({}) do |(k, v), memo|
             v = namer.get_name(v) if k == '@id' && v.is_a?(String) && blank_node?(v)
-            memo.merge(k => rename_bnodes(v))
+            memo[k] = rename_bnodes(v)
           end
         else
           node

lib/json/ld/frame.rb

@@ -273,15 +273,14 @@ def prune_bnodes(input, bnodes_to_clear)
       def cleanup_preserve(input)
         case input
         when Array
-          # If, after replacement, an array contains only the value null remove the value, leaving an empty array.
-          input.map { |o| cleanup_preserve(o) }
+          input.map! { |o| cleanup_preserve(o) }
         when Hash
           if input.key?('@preserve')
             # Replace with the content of `@preserve`
             cleanup_preserve(input['@preserve'].first)
           else
-            input.inject({}) do |memo, (k, v)|
-              memo.merge(k => cleanup_preserve(v))
+            input.transform_values do |v|
+              cleanup_preserve(v)
             end
           end
         else
@@ -298,10 +297,10 @@ def cleanup_null(input)
         case input
         when Array
           # If, after replacement, an array contains only the value null remove the value, leaving an empty array.
-          input.map { |o| cleanup_null(o) }.compact
+          input.map! { |o| cleanup_null(o) }.compact
         when Hash
-          input.inject({}) do |memo, (k, v)|
-            memo.merge(k => cleanup_null(v))
+          input.transform_values do |v|
+            cleanup_null(v)
           end
         when '@null'
           # If the value from the key-pair is @null, replace the value with null