code: function( input, charset ) {
      if( charset && !Buffer.isBuffer( input ) ) {
        return MIME.Iconv.encode( input, charset )
      } else {
        return Buffer.isBuffer( input )
          ? input.toString( 'base64' )
          : Buffer.from( input ).toString( 'base64' )
      }
    }
docs: Base64 encodes a buffer or string.
  
  @param  {String|Buffer} input
  @param  {String} charset
  @return {String}