1 files changed, 29 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
new file mode 100644
index 0000000000..6064e92f20
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/object/inclusion.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class Object
+  # Returns true if this object is included in the argument. Argument must be
+  # any object which responds to +#include?+. Usage:
+  #
+  #   characters = ["Konata", "Kagami", "Tsukasa"]
+  #   "Konata".in?(characters) # => true
+  #
+  # This will throw an +ArgumentError+ if the argument doesn't respond
+  # to +#include?+.
+  def in?(another_object)
+    another_object.include?(self)
+  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].presence_in %w( project calendar )
+  #
+  # This will throw an +ArgumentError+ if the argument doesn't respond to +#include?+.
+  #
+  # @return [Object]
+  def presence_in(another_object)
+    in?(another_object) ? self : nil
+  end
+end