code: function (type) {
    var handlers = { 'html': beautify.html, 'css': beautify.css, 'js': beautify.js };
  
    if (type === undefined) {
      return beautify;
    }
  
    if (type in handlers) {
      return handlers[type];
    }
  
    throw new Error('Unrecognized beautifier type:', type);
  }
docs: Method returns beautify handler for specific type of file.
  @param  {String} type - type of file e.g. html or js.
  @return {Object}      - beautify object.