make json a valid data format

features/data.feature

@@ -6,6 +6,11 @@ Feature: Local Data API
     When I go to "/data.html"
     Then I should see "One:Two"
   
+  Scenario: Rendering json
+    Given the Server is running at "test-app"
+    When I go to "/data3.html"
+    Then I should see "One:Two"
+  
   Scenario: Rendering liquid
     Given the Server is running at "test-app"
     When I go to "/data2.html"

fixtures/test-app/config.rb

@@ -20,6 +20,7 @@ with_layout false do
   page "/slim.html"
   page "/data.html"
   page "/data2.html"
+  page "/data3.html"
   page "/liquid_master.html"
   page "/page-classes.html"
   page "/sub1/page-classes.html"

fixtures/test-app/data/test2.json

@@ -0,0 +1,4 @@
+[
+  { "title": "One" },
+  { "title": "Two" }
+]

fixtures/test-app/source/data3.html.erb

@@ -0,0 +1 @@
+<%= data.test2.map { |r| r.title }.join(":") %>

lib/middleman/core_extensions/data.rb

@@ -1,4 +1,5 @@
 require "yaml"
+require "active_support/json"
 require "thor"
 
 module Middleman::CoreExtensions::Data
@@ -38,7 +39,12 @@ module Middleman::CoreExtensions::Data
           response = YAML.load_file(file_path) 
         else
           file_path = File.join(@app.root, @app.data_dir, "#{path}.yaml")
-          response = YAML.load_file(file_path) if File.exists? file_path
+          if File.exists? file_path
+            response = YAML.load_file(file_path)
+          else
+            file_path = File.join(@app.root, @app.data_dir, "#{path}.json")
+            response = ActiveSupport::JSON.decode(File.read(file_path)) if File.exists? file_path
+          end
         end
       end
       
@@ -75,6 +81,12 @@ module Middleman::CoreExtensions::Data
         data[p] = data_for_path(p)
       end
       
+      json_path = File.join(@app.root, @app.data_dir, "*.json")
+      Dir[json_path].each do |f|
+        p = f.split("/").last.gsub(".json", "")
+        data[p] = data_for_path(p)
+      end
+      
       data
     end