Added Object#present_in to simplify value whitelisting

1 files changed, 12 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/object/inclusion.rb b/activesupport/lib/active_support/core_ext/object/inclusion.rb
index b5671f66d0..141f19e7b3 100644
--- a/activesupport/lib/active_support/core_ext/object/inclusion.rb
+++ b/activesupport/lib/active_support/core_ext/object/inclusion.rb
@@ -12,4 +12,16 @@ class Object
   rescue NoMethodError
     raise ArgumentError.new("The parameter passed to #in? must respond to #include?")
   end
+
+  # Returns the receiver if it's included in the argument otherwise returns +nil+.
+  # Argument must be any object which responds to +#include?+. Usage:
+  #
+  #   params[:bucket_type].present_in %w( project calendar )
+  #
+  # This will throw an ArgumentError if the argument doesn't respond to +#include?+.
+  #
+  # @return [Object]
+  def present_in(another_object)
+    self.in?(another_object) ? self : nil
+  end
 end