grunt watcher for multiple-to-multiple coffee-to-js compililation (with source maps)

gistfile1.txt

###
  command line: grunt watch
###
# global module:false

module.exports = (grunt) ->

  # Project configuration.
  grunt.initConfig
    watch:
      coffee:
        files: '**/*.coffee',
        tasks: 'coffee'

    coffee:
      src_to_multiple:
        options:
          sourceMap: true
        expand: true,
        flatten: false,
        cwd: 'assets/src/coffee',
        src: ['**/*.coffee'],
        dest: 'assets/js',
        ext: '.js'


  grunt.loadNpmTasks "grunt-contrib-coffee"
  grunt.loadNpmTasks('grunt-contrib-watch')
  # Default task.
  grunt.registerTask "default", "watch"

  grunt.event.on('watch', (action, filepath) -> (grunt.log.writeln(filepath + ' has ' + action)))