Parses an XML document or element into a JavaScript Object (JSON)

xml2json.js

/**
 * Parses an XML document or element into a JavaScript Object.
 *
 * To turn the object into JSON, use JSON.stringify().
 *
 * This function is heavily inspired by:
 * - [Converting Between XML and JSON]{@link http://www.xml.com/pub/a/2006/05/31/converting-between-xml-and-json.html}
 * - [xmltodict]{@link https://github.com/martinblech/xmltodict} Python library.
 * Thank you very much for both of two.
 *
 * @param {Element | Document} root An XML document or element to be parsed.
 * @return {Object} A JavaScript Object.
 * @license Public Domain.
 */
function xmlToObject(root) {
  if (root.nodeType !== Node.DOCUMENT_NODE && root.nodeType !== Node.ELEMENT_NODE) {
    return undefined;
  }

  root.normalize();

  let obj = {};

  // Add attributes first.
  if (root.nodeType === Node.ELEMENT_NODE && root.hasAttributes()) {
    for (let attribute of root.attributes) {
      obj["@" + attribute.name] = attribute.value;
    }
  }

  // Add child elements.
  for (let element of root.children) {
    let name = element.nodeName;
    let value = xmlToObject(element);

    if (obj.hasOwnProperty(name)) {
      if (Array.isArray(obj[name])) {
        obj[name].push(value);
      } else {
        obj[name] = [obj[name], value];
      }
    } else {
      obj[name] = value;
    }
  }

  if (root.nodeType === Node.ELEMENT_NODE) {
    // Get text content from child text-like elements (text and CDATA).
    //
    // Unlike Stefan Goessner's original parser, this parser will not add elements in mixed content to the text.
    // Also, this parser doesn't parse CDATA section separately.
    // The value of CDATA node will simply be concatenated to the text.
    const textNodes = Array.prototype.filter.call(root.childNodes,
            it => it.nodeType === Node.CDATA_SECTION_NODE
                || (it.nodeType === Node.TEXT_NODE && /[^\t\n\r ]/.test(it.nodeValue)))
        .map(it => it.nodeValue);
    const text = textNodes.length > 0 ? textNodes.join('') : null;

    // Add the text content at last.
    if (Object.getOwnPropertyNames(obj).length === 0) {
      obj = text;
    } else if (text !== null) {
      obj["#text"] = text;
    }
  }

  return obj;
};

// const text = `<e>text</e>`;
// const document = (new DOMParser()).parseFromString(text, "application/xml");
// console.log(JSON.stringify(xmlToObject(document)));