Compile all coffee and compass files recursively within an project with grunt.

Gruntfile.js

module.exports = function( grunt ) {


// Compile all coffee and compass files recursively within an project with grunt.

// Usage: 

// > cd <my-project>

// > npm install grunt-contrib-watch
// > npm install grunt-contrib-coffee
// > npm install grunt-contrib-compass

// > grunt assets_config 
// this generates an assets_config.js file, so when you create new coffee or sass file you have to rerun this task.

// > grunt watch


  if (grunt.file.exists('assets_config.js')) {
   var config = grunt.file.readJSON('assets_config.js');
   grunt.initConfig(config);
  };

  grunt.registerTask('assets_config', 'search all modules', function() {

   var compass = grunt.config.get('compass') || {};
   var coffee = grunt.config.get('coffee') || {};
   var watch = grunt.config.get('watch') || {};

   grunt.file.recurse('.', function(abspath, rootdir, subdir, filename) {
     if (!subdir) {
       return false;
     };

     if (subdir.indexOf('/sass') !== -1) {

       if (!(subdir in compass)) {
         var stylesheets_dir = subdir.split("sass").join('') + 'stylesheets';

         watch[subdir] = {
           files: [subdir + '/*.{scss,sass}'],
           tasks: ['compass:' + subdir]
         };

         compass[subdir] = {
           options: {
             sassDir: subdir,
             cssDir: stylesheets_dir
           }
         };

       };

     };

     if (filename.indexOf('.coffee') !== -1) {

       coffee[subdir] = coffee[subdir] || { 
         files: {},
         options: {
           sourceMap: true
         },
       };

       var javascripts_dir = subdir.split("coffeescripts").join('') + 'javascripts';

       if (!(subdir in watch)) {

         watch[subdir] = {
           // files: '<config.coffee.' + subdir +'.files>', // [subdir + '/*.coffee'],
           files: [subdir + '/*.coffee'],
           tasks: ['coffee:' + subdir]
         };

       }

       coffee[subdir].files[javascripts_dir + '/' + filename  + '.js'] = abspath;

     }

   });

   var asset_config = {
     compass: compass,
     coffee: coffee,
     watch: watch
   };

   grunt.file.delete('assets_config.js');
   grunt.file.write('assets_config.js', JSON.stringify(asset_config));

  });

  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-contrib-coffee');
  grunt.loadNpmTasks('grunt-contrib-compass');


}