Allow decorators to be inferred (Take 3)

lib/draper/base.rb

@@ -93,7 +93,13 @@ module Draper
     # @param [Object] instance(s) to wrap
     # @param [Hash] options (optional)
     def self.decorate(input, options = {})
-      input.respond_to?(:each) ? Draper::DecoratedEnumerableProxy.new(input, self, options) : new(input, options)
+      if input.respond_to?(:each)
+        Draper::DecoratedEnumerableProxy.new(input, self, options)
+      elsif options[:infer]
+        input.decorator(options)
+      else
+        new(input, options)
+      end
     end
 
     # Fetch all instances of the decorated class and decorate them.

lib/draper/decorated_enumerable_proxy.rb

@@ -7,11 +7,11 @@ module Draper
     end
 
     def each(&block)
-      @wrapped_collection.each { |member| block.call(@klass.new(member, @options)) }
+      @wrapped_collection.each { |member| block.call(@klass.decorate(member, @options)) }
     end
 
     def to_ary
-      @wrapped_collection.map { |member| @klass.new(member, @options) }
+      @wrapped_collection.map { |member| @klass.decorate(member, @options) }
     end
 
     def method_missing (method, *args, &block)

lib/draper/model_support.rb

@@ -1,9 +1,9 @@
 module Draper::ModelSupport
   def decorator(options = {})
-    @decorator ||= "#{self.class.name}Decorator".constantize.decorate(self, options)
+    @decorator ||= "#{self.class.name}Decorator".constantize.decorate(self, options.merge(:infer => false))
     block_given? ? yield(@decorator) : @decorator
   end
-  
+
   alias :decorate :decorator
 
   module ClassMethods

spec/draper/base_spec.rb

@@ -181,6 +181,47 @@ describe Draper::Base do
       end
     end
 
+    context "does not infer collections by default" do
+      subject { Draper::Base.decorate(source).to_ary }
+
+      let(:source) { [Product.new, Widget.new] }
+
+      it "returns a collection of wrapped objects all with the same decorator" do
+        subject.first.class.name.should eql 'Draper::Base'
+        subject.last.class.name.should eql  'Draper::Base'
+      end
+    end
+
+    context "does not infer single items by default" do
+      subject { Draper::Base.decorate(source) }
+
+      let(:source) { Product.new }
+
+      it "returns a decorator of the type explicity used in the call" do
+        subject.class.should eql Draper::Base
+      end
+    end
+
+    context "returns a collection containing only the explicit decorator used in the call" do
+      subject { Draper::Base.decorate(source, :infer => true).to_ary }
+
+      let(:source) { [Product.new, Widget.new] }
+
+      it "returns a mixed collection of wrapped objects" do
+        subject.first.class.should eql ProductDecorator
+        subject.last.class.should eql WidgetDecorator
+      end
+    end
+
+    context "when given a single object" do
+      subject { Draper::Base.decorate(source, :infer => true) }
+
+      let(:source) { Product.new }
+
+      it "can also infer its decorator" do
+        subject.class.should eql ProductDecorator
+      end
+    end
   end
 
   context('.==') do

spec/samples/widget.rb

@@ -0,0 +1,2 @@
+class Widget < Product
+end

spec/samples/widget_decorator.rb

@@ -0,0 +1,2 @@
+class WidgetDecorator < ProductDecorator
+end

spec/support/samples/widget.rb

@@ -0,0 +1,2 @@
+class Widget < Product
+end

spec/support/samples/widget_decorator.rb

@@ -0,0 +1,2 @@
+class WidgetDecorator < ProductDecorator
+end