Add suffix code for context during server rendering

README.md

@@ -205,6 +205,17 @@ react_component('HelloMessage', {name: 'John'}, {prerender: true})
 ```
 This will return the fully rendered component markup, and as long as you have included the `react_ujs` script in your page, then the component will also be instantiated and mounted on the client.
 
+#### Preload globals
+
+If you want to preload some global variables, generated by Gon for example,
+use the same view helper `react_component`, and pass in `context_suffix: 'some loading javascript'` in the `options` hash.
+
+```erb
+react_component('HelloMessage', {name: 'John'}, {prerender: true, context_suffix: 'window.myVar = 123;'})
+```
+
+This will return the fully rendered component markup, that can use preloaded variables
+
 ## Configuring
 
 ### Variants

lib/react/rails/view_helper.rb

@@ -8,7 +8,8 @@ module ViewHelper
       #
       def react_component(name, args = {}, options = {}, &block)
         options = {:tag => options} if options.is_a?(Symbol)
-        block = Proc.new{concat React::Renderer.render(name, args)} if options[:prerender] == true
+        context_suffix = options.delete(:context_suffix) || ''
+        block = Proc.new{concat React::Renderer.render(name, args, context_suffix)} if options[:prerender] == true
 
         html_options = options.reverse_merge(:data => {})
         html_options[:data].tap do |data|

lib/react/renderer.rb

@@ -21,9 +21,9 @@ def self.setup!(react_js, components_js, args={})
       @@pool = ConnectionPool.new(:size => args[:size]||10, :timeout => args[:timeout]||20) { self.new }
     end
 
-    def self.render(component, args={})
+    def self.render(component, args={}, context_suffix='')
       @@pool.with do |renderer|
-        renderer.render(component, args)
+        renderer.render(component, args, context_suffix)
       end
     end
 
@@ -62,18 +62,26 @@ def self.react_props(args={})
       end
     end
 
-    def context
-      @context ||= ExecJS.compile(self.class.combined_js)
+    def context(suffix_code='')
+      if suffix_code.present?
+        reset_context(suffix_code)
+      else
+        @context ||= ExecJS.compile(self.class.combined_js)
+      end
+    end
+
+    def reset_context(suffix_code='')
+      @context = ExecJS.compile(self.class.combined_js + suffix_code)
     end
 
-    def render(component, args={})
+    def render(component, args={}, context_suffix='')
       react_props = React::Renderer.react_props(args)
       jscode = <<-JS
         function() {
           return React.renderToString(React.createElement(#{component}, #{react_props}));
         }()
       JS
-      context.eval(jscode).html_safe
+      context(context_suffix).eval(jscode).html_safe
     rescue ExecJS::ProgramError => e
       raise PrerenderError.new(component, react_props, e)
     end

test/dummy/app/assets/javascripts/components/TodoGlobalList.js.jsx

@@ -0,0 +1,18 @@
+TodoGlobalList = React.createClass({
+    getInitialState: function() {
+        return({mounted: "nope"});
+    },
+    componentWillMount: function() {
+        this.setState({mounted: 'yep'});
+    },
+    render: function() {
+        return (
+            <ul>
+                <li id='status'>{this.state.mounted}</li>
+        {todos.map(function(todo, i) {
+            return (<Todo key={i} todo={todo} />)
+        })}
+            </ul>
+            )
+    }
+})

test/react_renderer_test.rb

@@ -18,6 +18,12 @@ class ReactRendererTest < ActiveSupport::TestCase
     assert_match /data-react-checksum/, result
   end
 
+  test 'Server rendering with context suffix ' do
+    result = React::Renderer.render "TodoGlobalList", {}, 'window.todos=["todo1","todo2","todo3"];'
+    assert_match /todo1.*todo2.*todo3/, result
+    assert_match /data-react-checksum/, result
+  end
+
   test 'Rendering does not throw an exception when console log api is used' do
     %W(error info log warn).each do |fn|
       assert_nothing_raised(ExecJS::ProgramError) do