Added element and collection proxies to RJS [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3587 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

@@ -1,5 +1,15 @@
 *SVN*
 
+* Added element and collection proxies to RJS [DHH]. Examples:
+
+    page['blank_slate']                  # => $('blank_slate');
+    page['blank_slate'].show             # => $('blank_slate').show();
+    page['blank_slate'].show('first').up # => $('blank_slate').show('first').up();
+    
+    page.select('p')                      # => $$('p');
+    page.select('p.welcome b').first      # => $$('p.welcome b').first();
+    page.select('p.welcome b').first.hide # => $$('p.welcome b').first().hide();
+
 * Add JavaScriptGenerator#replace_element for replacing an element's "outer HTML". #3246 [tom@craz8.com, Sam Stephenson]
 
 * Remove over-engineered form_for code for a leaner implementation. [Nicholas Seckar]

actionpack/lib/action_view/helpers/prototype_helper.rb

@@ -416,6 +416,26 @@ module ActionView
         def to_s #:nodoc:
           @lines * $/
         end
+
+        # Returns a element reference by finding it through +id+ in the DOM. This element can then be
+        # used for further method calls. Examples:
+        #
+        #   page['blank_slate']                  # => $('blank_slate');
+        #   page['blank_slate'].show             # => $('blank_slate').show();
+        #   page['blank_slate'].show('first').up # => $('blank_slate').show('first').up();
+        def [](id)
+          JavaScriptElementProxy.new(self, "$('#{id}')")
+        end
+
+        # Returns a collection reference by finding it through a CSS +pattern+ in the DOM. This collection can then be
+        # used for further method calls. Examples:
+        #
+        #   page.select('p')                      # => $$('p');
+        #   page.select('p.welcome b').first      # => $$('p.welcome b').first();
+        #   page.select('p.welcome b').first.hide # => $$('p.welcome b').first().hide();
+        def select(pattern)
+          JavaScriptElementProxy.new(self, "$$('#{pattern}')")
+        end
   
         # Inserts HTML at the specified +position+ relative to the DOM element
         # identified by the given +id+.
@@ -644,5 +664,24 @@ module ActionView
         callbacks
       end
     end
+
+    # Converts chained method calls on DOM proxy elements into JavaScript chains 
+    class JavaScriptElementProxy < Builder::BlankSlate #:nodoc:
+      def initialize(generator, root)
+        @generator = generator
+        @generator << root
+      end
+      
+      private
+        def method_missing(method, *arguments)
+          method_chain = @generator.instance_variable_get("@lines")
+
+          last_method  = method_chain[-1]
+          method_chain[-1] = last_method[0..-2] if last_method[-1..-1] == ";" # strip trailing ; from last method call
+          method_chain[-1] += ".#{method}(#{@generator.send(:arguments_for_call, arguments)});"
+
+          self
+        end
+    end
   end
 end

actionpack/test/template/prototype_helper_test.rb

@@ -227,4 +227,27 @@ new Insertion.Bottom("element", "<p>This is a test</p>");
 Element.update("baz", "<p>This is a test</p>");
     EOS
   end
-end
+
+  def test_element_access
+    assert_equal %($('hello');), @generator['hello']
+  end
+
+  def test_element_proxy_one_deep
+    @generator['hello'].hide
+    assert_equal %($('hello').hide();), @generator.to_s
+  end
+
+  def test_element_proxy_two_deep
+    @generator['hello'].hide("first").display
+    assert_equal %($('hello').hide("first").display();), @generator.to_s
+  end
+  
+  def test_select_access
+    assert_equal %($$('div.hello');), @generator.select('div.hello')
+  end
+
+  def test_select_proxy_one_deep
+    @generator.select('p.welcome b').first.hide
+    assert_equal %($$('p.welcome b').first().hide();), @generator.to_s
+  end
+end