Fix JSX when execjs uses therubyracer.

Author: quark-zju

Diff for: Appraisals

@@ -9,3 +9,8 @@ end
 appraise "rails-4.0" do
   gem 'rails', '~> 4.0'
 end
+
+appraise "rails-4.0-with-therubyracer" do
+  gem 'rails', '~> 4.0'
+  gem 'therubyracer', '0.12.0', :platform => :mri
+end

Diff for: lib/react/jsx.rb

@@ -6,7 +6,11 @@ module React
   module JSX
     def self.context
       # TODO: create React::Source::contents_for
-      contents = File.read(React::Source.bundled_path_for('JSXTransformer.js'))
+      contents =
+        # If execjs uses therubyracer, there is no 'global'. Make sure
+        # we have it so JSX script can work properly.
+        'var global = global || this;' +
+        File.read(React::Source.bundled_path_for('JSXTransformer.js'))
       @context ||= ExecJS.compile(contents)
     end