code: function returns(error, html, cb) {
      var fn = typeof cb === 'function';
  
      if (error) {
        debug('Error received: %s', error.message);
  
        if (fn) cb(error);
        return minimize.emit('error', error);
      }
  
      if (fn) return cb(null, html);
      return html;
    }
docs: (A)synchronously return or callback with HTML.
  
  @param {Error} error Runtime error
  @param {String} html minimized HTML
  @param {Function} cb optional callback
  @returns {String} HTML
  @api private