Grape::Entity#serializable_hash should call #serializable_hash elementwise if the data returned from #value_for is an array for which each element responds to that method so that nested Grape::Entity presentation works correctly with arrays of values.

Author: goodwink

lib/grape/entity.rb

@@ -233,8 +233,15 @@ def serializable_hash(runtime_options = {})
       opts = options.merge(runtime_options || {})
       exposures.inject({}) do |output, (attribute, exposure_options)|
         partial_output = value_for(attribute, opts) if conditions_met?(exposure_options, opts)
-        partial_output = partial_output.serializable_hash(runtime_options) if partial_output.respond_to? :serializable_hash
-        output[key_for(attribute)] = partial_output
+        
+        output[key_for(attribute)] =
+          if partial_output.respond_to? :serializable_hash
+            partial_output.serializable_hash(runtime_options)
+          elsif partial_output.kind_of?(Array) && !partial_output.map {|o| o.respond_to? :serializable_hash}.include?(false)
+            partial_output.map {|o| o.serializable_hash}
+          else
+            partial_output
+          end
 
         output
       end

spec/grape/entity_spec.rb

@@ -279,6 +279,28 @@ def embedded
         presenter = fresh_class.new(SimpleExample.new)
         presenter.serializable_hash.should == {:name => "abc", :embedded => {:abc => "def"}}
       end
+
+      it 'should serialize embedded arrays of objects which respond to #serializable_hash' do
+        class EmbeddedExample
+          def serializable_hash(opts = {})
+            {:abc => 'def'}
+          end
+        end
+
+        class SimpleExample
+          def name
+            "abc"
+          end
+
+          def embedded
+            [EmbeddedExample.new, EmbeddedExample.new]
+          end
+        end
+
+        fresh_class.expose :name, :embedded
+        presenter = fresh_class.new(SimpleExample.new)
+        presenter.serializable_hash.should == {:name => "abc", :embedded => [{:abc => "def"}, {:abc => "def"}]}
+      end
     end
 
     describe '#value_for' do