JSFiddle - React, Tailwind, and code Playground

HTML

<xml>
    <element>value</element>
    <duplicate>dup1</duplicate>
    <duplicate>dup2</duplicate>
</xml>

JavaScript

function parse(xml) {
	var o = {};
    $(xml).find('*').andSelf().contents().filter(function() {
		return this.nodeType == 3 && $.trim(this.nodeValue);
	}).each(function() {
		var p = this.parentNode.nodeName;
		if (!o[p]) o[p] = [];
		o[p].push(this.nodeValue);
	});
    return o;
}
console.dir(parse($("xml").get(0)));