Merge pull request #25008 from lvl0nax/as_enumarable_index_by_refacto…

…ring Perfomance fix for ActiveSupport Enumerable#index_by
rails · May 14, 2016 · 4046ac7 · 4046ac7
2 parents b981369 + 6751b10
commit 4046ac7
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb
@@ -34,7 +34,9 @@ def sum(identity = nil, &block)
   #     => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
   def index_by
     if block_given?
-      Hash[map { |elem| [yield(elem), elem] }]
+      result = {}
+      each { |elem| result[yield(elem)] = elem }
+      result
     else
       to_enum(:index_by) { size if respond_to?(:size) }
     end