formatXML.js (without jQuery, supports XML empty tags, optionally escape for HTML)

formatXML.js

/* pretty-print / beautify XML strings
 * Released under the MIT License (MIT)
 * Copyright (c) 2021 Joe DF
 * 
 * Modified from (Martin Kurtsson):
 * https://gist.github.com/kurtsson/3f1c8efc0ccd549c9e31
 *
 * which is based on (Stuart Powers):
 * https://gist.github.com/sente/1083506 
 */
function formatXml(xml, padChar = '\t', escapeHTML = false, useEmptyTags = true) {
	var formatted = '', prevLine = '', newLine = '\r\n', pad = 0;
	
	var reg = /(>)(<)(\/*)/g;
	xml = xml.toString().replace(reg, '$1'+newLine+'$2$3');
	var nodes = xml.split(newLine);
	
	for (var n in nodes) {
		var node = nodes[n];
		var indent = 0;
		if (node.match(/.+<\/\w[^>]*>$/)) {
			indent = 0;
		} else if (node.match(/^<\/\w/)) {
			if (pad !== 0) {
				pad -= 1;
			}
		} else if (node.match(/^<\w[^>]*[^\/]>.*$/)) {
			indent = 1;
		} else {
			indent = 0;
		}

		var padding = '';
		for (var i = 0; i < pad; i++) {
			padding += padChar;
		}

		var currLine = node + newLine;

		if (prevLine.trim().replace('<', '</') == node.trim()) {
			formatted = formatted.slice(0, 0 - newLine.length - 1);
			if (useEmptyTags)
				formatted += '/>' + newLine;
			else
				formatted += '>' + currLine;
		} else {
			formatted += padding + currLine;
		}

		pad += indent;

		prevLine = currLine;
	}
	if (escapeHTML)
		return formatted.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/ /g, '&nbsp;');
	return formatted;
}