Add `ActionController::Parameters#dig`

This method will only be added when used with Ruby 2.3.0 or greater.
This method has the same behavior as `Hash#dig`, except it will convert
hashes to `ActionController::Parameters`, similar to `#[]` and `#fetch`.

1 files changed, 20 insertions, 0 deletions

diff --git a/actionpack/test/controller/parameters/accessors_test.rb b/actionpack/test/controller/parameters/accessors_test.rb
index cea265f9ab..17c62dc3fe 100644
--- a/actionpack/test/controller/parameters/accessors_test.rb
+++ b/actionpack/test/controller/parameters/accessors_test.rb
@@ -194,4 +194,24 @@ class ParametersAccessorsTest < ActiveSupport::TestCase
 
     assert_match(/permitted: true/, @params.inspect)
   end
+
+  if Hash.method_defined?(:dig)
+    test "#dig delegates the dig method to its values" do
+      assert_equal "David", @params.dig(:person, :name, :first)
+      assert_equal "Chicago", @params.dig(:person, :addresses, 0, :city)
+    end
+
+    test "#dig converts hashes to parameters" do
+      assert_kind_of ActionController::Parameters, @params.dig(:person)
+      assert_kind_of ActionController::Parameters, @params.dig(:person, :addresses, 0)
+      assert @params.dig(:person, :addresses).all? do |value|
+        value.is_a?(ActionController::Parameters)
+      end
+    end
+  else
+    test "ActionController::Parameters does not respond to #dig on Ruby 2.2" do
+      assert_not ActionController::Parameters.method_defined?(:dig)
+      assert_not @params.respond_to?(:dig)
+    end
+  end
 end