Allow for drop-in replacement using recommended files structure

Author: jtmalinowski

lib/react/jsx.rb

@@ -5,15 +5,20 @@
 
 module React
   module JSX
-    # lazily loaded during first request
     def self.context
-      # TODO: create React::Source::contents_for
-      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)
+      # lazily loaded during first request and reloaded every time when in dev or test
+      unless @context && ::Rails.env.production?
+
+        # TODO: create React::Source::contents_for
+        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
+
+      @context
     end
 
     def self.transform(code)

lib/react/rails/railtie.rb

@@ -28,9 +28,17 @@ class Railtie < ::Rails::Railtie
                        tmp_path.join('react.js'))
           FileUtils.cp(::React::Source.bundled_path_for('JSXTransformer.js'),
                        tmp_path.join('JSXTransformer.js'))
+          app.assets.prepend_path tmp_path
 
-          # Make sure it can be found
-          app.assets.append_path(tmp_path)
+          # Allow overriding react files that are not based on environment
+          # e.g. /vendor/react/JSXTransformer.js
+          dropin_path = app.root.join("vendor/assets/react")
+          app.assets.prepend_path dropin_path if dropin_path.exist?
+
+          # Allow overriding react files that are based on environment
+          # e.g. /vendor/react/react.js
+          dropin_path_env = app.root.join("vendor/assets/react/#{variant}")
+          app.assets.prepend_path dropin_path_env if dropin_path_env.exist?
         end
       end
     end

test/dummy/app/assets/javascripts/example2.js.jsx

@@ -0,0 +1,2 @@
+/** @jsx React.DOM */
+<div/>;

test/dummy/config/environments/test.rb

@@ -5,7 +5,11 @@
   # test suite. You never need to work with it otherwise. Remember that
   # your test database is "scratch space" for the test suite and is wiped
   # and recreated between test runs. Don't rely on the data there!
-  config.cache_classes = true
+
+  # we need this to reload the jsx transformer when different version is dropped in
+  config.cache_classes = false
+  config.reload_plugins = true
+  config.assets.cache_store = :null_store
 
   # Do not eager load code on boot. This avoids loading your whole application
   # just for the purpose of running a single test. If you are using a tool that
@@ -33,4 +37,6 @@
 
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr
+
+  config.react.variant = :test
 end

test/dummy/vendor/assets/react/JSXTransformer__.js

@@ -0,0 +1,7 @@
+var JSXTransformer = {
+  transform: function () {
+    return {
+      code: 'test_confirmation_token_jsx_transformed;'
+    };
+  }
+};

test/dummy/vendor/assets/react/test/react__.js

@@ -0,0 +1 @@
+'test_confirmation_token_react_content';

test/jsxtransform_test.rb

@@ -1,6 +1,7 @@
 require 'test_helper'
+require 'fileutils'
 
-# The transformer is inserting a newline after the docblock for some reason...
+# Sprockets is inserting a newline after the docblock for some reason...
 EXPECTED_JS = <<eos
 /** @jsx React.DOM */
 
@@ -28,6 +29,19 @@ class JSXTransformTest < ActionDispatch::IntegrationTest
     get 'assets/example.js'
     assert_response :success
     assert_equal EXPECTED_JS, @response.body
+    FileUtils.rm_r CACHE_PATH if CACHE_PATH.exist?
+  end
+
+  test 'can use dropped in version of JSX transformer' do
+    hidden_path = File.expand_path("../dummy/vendor/assets/react/JSXTransformer__.js",  __FILE__)
+    replacing_path = File.expand_path("../dummy/vendor/assets/react/JSXTransformer.js",  __FILE__)
+
+    FileUtils.mv hidden_path, replacing_path
+    get 'assets/example2.js'
+    assert_response :success
+    assert_equal 'test_confirmation_token_jsx_transformed;', @response.body
+    FileUtils.mv replacing_path, hidden_path
+    FileUtils.rm_r CACHE_PATH if CACHE_PATH.exist?
   end
 
   test 'asset pipeline should transform JSX + Coffeescript' do

test/react_test.rb

@@ -0,0 +1,33 @@
+require 'test_helper'
+require 'fileutils'
+
+class ReactTest < ActionDispatch::IntegrationTest
+
+  test 'asset pipeline should deliver react file in a non-production variant' do
+    actual_react_file_path = File.expand_path("../dummy/tmp/react-rails/react.js",  __FILE__)
+    actual_react_file_content = File.read actual_react_file_path
+
+    react_file_token = "'test_confirmation_token_react_content_non_production';\n";
+    File.open(actual_react_file_path, 'w') {|f| f.write react_file_token}
+
+    get 'assets/react.js'
+    assert_response :success
+    assert_equal react_file_token, @response.body
+
+    File.open(actual_react_file_path, 'w') {|f| f.write actual_react_file_content}
+    FileUtils.rm_r CACHE_PATH if CACHE_PATH.exist?
+  end
+
+  test 'asset pipeline should deliver drop-in react file replacement' do
+    hidden_path = File.expand_path("../dummy/vendor/assets/react/test/react__.js",  __FILE__)
+    replacing_path = File.expand_path("../dummy/vendor/assets/react/test/react.js",  __FILE__)
+
+    FileUtils.mv hidden_path, replacing_path
+    get 'assets/react.js'
+    assert_response :success
+    assert_equal "'test_confirmation_token_react_content';\n", @response.body
+    FileUtils.mv replacing_path, hidden_path
+    FileUtils.rm_r CACHE_PATH if CACHE_PATH.exist?
+  end
+
+end

test/test_helper.rb

@@ -3,6 +3,9 @@
 
 require File.expand_path("../dummy/config/environment.rb",  __FILE__)
 require "rails/test_help"
+require "pathname"
+
+CACHE_PATH = Pathname.new File.expand_path("../dummy/tmp/cache",  __FILE__)
 
 Rails.backtrace_cleaner.remove_silencers!