From 9256ae8a389fd40f9e4f152737de0fb2c6059daf Mon Sep 17 00:00:00 2001
From: Alexander Pauly <alex.pauly@posteo.de>
Date: Thu, 9 Jan 2020 13:21:51 +0100
Subject: [PATCH] Reduce number of created objects in Hash#as_json

---
 activesupport/lib/active_support/core_ext/object/json.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/activesupport/lib/active_support/core_ext/object/json.rb b/activesupport/lib/active_support/core_ext/object/json.rb
index 416059d17bc..d92af19137c 100644
--- a/activesupport/lib/active_support/core_ext/object/json.rb
+++ b/activesupport/lib/active_support/core_ext/object/json.rb
@@ -169,7 +169,11 @@ class Hash
       self
     end
 
-    Hash[subset.map { |k, v| [k.to_s, options ? v.as_json(options.dup) : v.as_json] }]
+    result = {}
+    subset.each do |k, v|
+      result[k.to_s] = options ? v.as_json(options.dup) : v.as_json
+    end
+    result
   end
 end