code: function(input, source) {
    var output = input.toString();
  
    if (source.path.match(/\.js$/)) {
      output = output.replace(/(["'](do not )?use strict[\"\'];)/,
          'define(function(require, exports, module) {\n\n$1');
      output += '\n\n});\n';
    }
  
    return output;
  }
docs: A filter to munge CommonJS headers