code: function mapper(options, filePath) {
  	var cwd = options.cwd;
  	var base = options.base;
  
  	filePath = require.resolve(path.resolve(cwd, filePath));
  
  	if (options.bustCache) {
  		delete require.cache[filePath];
  	}
  
  	return {
  		cwd: cwd,
  		base: base,
  		path: filePath,
  		exports: require(filePath)
  	};
  }
docs: Map Reduce