Class Format

// Log an XML document with encoding that does not support certain special characters.
var xml = '<root><a><b>ಠ‿ಠ</b><b>ಠ‿ಠ</b></a></root>';
var document = XmlService.parse(xml);
var output = XmlService.getRawFormat()
    .setEncoding('ISO-8859-1')
    .format(document);
Logger.log(output);

// Log an XML document with each child node indented four spaces.
var xml = '<root><a><b>Text!</b><b>More text!</b></a></root>';
var document = XmlService.parse(xml);
var output = XmlService.getCompactFormat()
    .setIndent('    ')
    .format(document);
Logger.log(output);

// Log an XML document with several spaces and a pipe character in place of line breaks.
var xml = '<root><a><b>Text!</b><b>More text!</b></a></root>';
var document = XmlService.parse(xml);
var output = XmlService.getRawFormat()
    .setLineSeparator(' | ')
    .format(document);
Logger.log(output);