Function to convert XML to JSON

xmlToJson.js

/**
 * Changes XML to JSON
 * Modified version from here: http://davidwalsh.name/convert-xml-json
 * @param {string} xml XML DOM tree
 */
function xmlToJson(xml) {
  // Create the return object
  var obj = {};

  if (xml.nodeType == 1) {
    // element
    // do attributes
    if (xml.attributes.length > 0) {
      obj["@attributes"] = {};
      for (var j = 0; j < xml.attributes.length; j++) {
        var attribute = xml.attributes.item(j);
        obj["@attributes"][attribute.nodeName] = attribute.nodeValue;
      }
    }
  } else if (xml.nodeType == 3) {
    // text
    obj = xml.nodeValue;
  }

  // do children
  // If all text nodes inside, get concatenated text from them.
  var textNodes = [].slice.call(xml.childNodes).filter(function(node) {
    return node.nodeType === 3;
  });
  if (xml.hasChildNodes() && xml.childNodes.length === textNodes.length) {
    obj = [].slice.call(xml.childNodes).reduce(function(text, node) {
      return text + node.nodeValue;
    }, "");
  } else if (xml.hasChildNodes()) {
    for (var i = 0; i < xml.childNodes.length; i++) {
      var item = xml.childNodes.item(i);
      var nodeName = item.nodeName;
      if (typeof obj[nodeName] == "undefined") {
        obj[nodeName] = xmlToJson(item);
      } else {
        if (typeof obj[nodeName].push == "undefined") {
          var old = obj[nodeName];
          obj[nodeName] = [];
          obj[nodeName].push(old);
        }
        obj[nodeName].push(xmlToJson(item));
      }
    }
  }
  return obj;
}

/*
Usage:

1. If you have an XML file URL:

const response = await fetch('file_url');
const xmlString = await response.text();
var XmlNode = new DOMParser().parseFromString(xmlString, 'text/xml');
xmlToJson(XmlNode);

2. If you have an XML as string:

var XmlNode = new DOMParser().parseFromString(yourXmlString, 'text/xml');
xmlToJson(XmlNode);

3. If you have the XML as a DOM Node:

xmlToJson(YourXmlNode);
*/

thank you!

I am facing an error " cannot convert undefined or null to object " in line 23