JS XML pretty print using XSLT

Example for an SO question: https://stackoverflow.com/questions/376373/pretty-printing-xml-with-javascript

by Artur Klesun

HTML

<body>
  <div>Pretty XML output follows...</div>
  <textarea class="output-holder" rows="10" cols = "30"></textarea>
</body>

JavaScript

var prettifyXml = function(sourceXml)
{
    var xmlDoc = new DOMParser().parseFromString(sourceXml, 'application/xml');
    var xsltDoc = new DOMParser().parseFromString([
      // describes how we want to modify the XML - indent everything
      '<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">',
      '<xsl:output omit-xml-declaration="yes" indent="yes"/>',
      '<xsl:template match="node()|@*">',
      '  <xsl:copy><xsl:apply-templates select="node()|@*"/></xsl:copy>',
      '</xsl:template>',
      '</xsl:stylesheet>',
    ].join('\n'), 'application/xml');

    var xsltProcessor = new XSLTProcessor();    
    xsltProcessor.importStylesheet(xsltDoc);
    var resultDoc = xsltProcessor.transformToDocument(xmlDoc);
    var resultXml = new XMLSerializer().serializeToString(resultDoc);
    return resultXml;
};
    
var prettyXml = prettifyXml('<root><node/></root>');
document.querySelector('.output-holder').value = prettyXml;