add an option for direct output in JS

README.md

@@ -162,7 +162,7 @@ There following options can be passed to Guard::CoffeeScript:
 
 ```ruby
 :input => 'coffeescripts'           # Relative path to the input directory.
-                                    # A suffix `/(.+\.coffee)` will be added to this option.
+                                    # A suffix /(.+\.coffee) will be added to this option.
                                     # default: nil
 
 :output => 'javascripts'            # Relative path to the output directory.
@@ -183,6 +183,10 @@ There following options can be passed to Guard::CoffeeScript:
 
 :all_on_start => true               # Regenerate all files on startup
                                     # default: false
+
+:error_to_js => true                # Print the Coffeescript error message directly in the
+                                    # JavaScript file
+                                    # default: false
 ```
 
 ### Output short notation

lib/guard/coffeescript.rb

@@ -18,6 +18,7 @@ class CoffeeScript < Guard
         :shallow      => false,
         :hide_success => false,
         :noop         => false,
+        :error_to_js  => false,
         :all_on_start => false
     }
 

lib/guard/coffeescript/runner.rb

@@ -60,6 +60,14 @@ def compile_files(files, watchers, options)
                 changed_files << write_javascript_file(content, file, directory, options)
               rescue => e
                 error_message = file + ': ' + e.message.to_s
+
+                if options[:error_to_js]
+                  js_error_message = %q(#{error_message})
+                  js_error_message = "var message = \"#{error_message} \";"
+                  js_error_message += "throw message;"
+                  changed_files << write_javascript_file(js_error_message, file, directory, options)
+                end
+
                 errors << error_message
                 Formatter.error(error_message)
               end