JSFiddle - React, Tailwind, and code Playground

CSS

li.selected ul {
    display: none
}

JavaScript

var txt = '<?xml version="1.0" encoding="UTF-8"?><bookstore>    <book category="cooking">        <title lang="en">Everyday Italian</title>        <author>Giada De Laurentiis</author>        <year>2005</year>        <price>30.00</price>    </book>    <book category="children">        <title lang="en">Harry Potter</title>        <author>J K. Rowling</author>        <year>2005</year>        <price>29.99</price>    </book>    <book category="web">        <title lang="en">XQuery Kick Start</title>        <author>James McGovern</author>        <author>Per Bothner</author>        <author>Kurt Cagle</author>        <author>James Linn</author>        <author>Vaidyanathan Nagarajan</author>        <year>2003</year>        <price>49.99</price>    </book>    <book category="web" cover="paperback">        <title lang="en">Learning XML</title>        <author>Erik T. Ray</author>        <year>2003</year>        <price>39.95</price>    </book></bookstore>';

// compare function for sorting
function compare(a,b) {
  if (a.name < b.name)
     return -1;
  if (a.name > b.name)
    return 1;
  return 0;
}

function parse(node) {
    if (node.nodeType != 1) return null;
    var result = {name: node.nodeName};
    var children = [];
    for (var i = 0; i < node.childNodes.length; i++) {
        var child = parse(node.childNodes[i]);
        if (child)
        {
            children.push(child);
        }
    }
    
    // sort children
    children.sort(compare);
    
    // store them
    result.children = children;
    return result;
}

// needs to be updated
function generate(node) {
    if (node.nodeType != 1) return "";
    var html = "<li>" + node.nodeName;
    var htmlForChildNodes = "";
    for (var i = 0; i < node.childNodes.length; i++) {
        htmlForChildNodes += generate(node.childNodes[i]);
    }
    if (htmlForChildNodes) {
        html += "<ul>" + htmlForChildNodes + "</ul>";
    }
    html += "</li>";
    return html;
}

if (window.DOMParser) {
    parser = new...