Convert XML to JSON (and back) using Javascript


How would you convert from XML to JSON and then back to XML?

The following tools work quite well, but aren't completely consistent:

Has anyone encountered this situation before?

I think this is the best one: Converting between XML and JSON

Be sure to read the accompanying article on the xml.com O'Reilly site, which goes into details of the problems with these conversions, which I think you will find enlightening. The fact that O'Reilly is hosting the article should indicate that Stefan's solution has merit.


https://github.com/abdmob/x2js - my own library (updated URL from http://code.google.com/p/x2js/):

This library provides XML to JSON (JavaScript Objects) and vice versa javascript conversion functions. The library is very small and doesn't require any other additional libraries.

API functions

  • new X2JS() - to create your instance to access all library functionality. Also you could specify optional configuration options here
  • X2JS.xml2json - Convert XML specified as DOM Object to JSON
  • X2JS.json2xml - Convert JSON to XML DOM Object
  • X2JS.xml_str2json - Convert XML specified as string to JSON
  • X2JS.json2xml_str - Convert JSON to XML string

Online Demo on http://jsfiddle.net/abdmob/gkxucxrj/1/

var x2js = new X2JS();
function convertXml2JSon() {
    $("#jsonArea").val(JSON.stringify(x2js.xml_str2json($("#xmlArea").val())));
}

function convertJSon2XML() {
    $("#xmlArea").val(x2js.json2xml_str($.parseJSON($("#jsonArea").val())));
}

convertXml2JSon();
convertJSon2XML();
$("#convertToJsonBtn").click(convertXml2JSon);
$("#convertToXmlBtn").click(convertJSon2XML);

These answers helped me a lot to make this function:

function xml2json(xml) {
  try {
    var obj = {};
    if (xml.children.length > 0) {
      for (var i = 0; i < xml.children.length; i++) {
        var item = xml.children.item(i);
        var nodeName = item.nodeName;

        if (typeof (obj[nodeName]) == "undefined") {
          obj[nodeName] = xml2json(item);
        } else {
          if (typeof (obj[nodeName].push) == "undefined") {
            var old = obj[nodeName];

            obj[nodeName] = [];
            obj[nodeName].push(old);
          }
          obj[nodeName].push(xml2json(item));
        }
      }
    } else {
      obj = xml.textContent;
    }
    return obj;
  } catch (e) {
      console.log(e.message);
  }
}

As long as you pass in a jquery dom/xml object: for me it was:

Jquery(this).find('content').eq(0)[0]

where content was the field I was storing my xml in.


A while back I wrote this tool https://bitbucket.org/surenrao/xml2json for my TV Watchlist app, hope this helps too.

Synopsys: A library to not only convert xml to json, but is also easy to debug (without circular errors) and recreate json back to xml. Features :- Parse xml to json object. Print json object back to xml. Can be used to save xml in IndexedDB as X2J objects. Print json object.


I would personally recommend this tool. It is an XML to JSON converter.

It is very lightweight and is in pure JavaScript. It needs no dependencies. You can simply add the functions to your code and use it as you wish.

It also takes the XML attributes into considerations.

var xml = ‘<person id=”1234” age=”30”><name>John Doe</name></person>’;
var json = xml2json(xml); 

console.log(json); 
// prints ‘{“person”: {“id”: “1234”, “age”: “30”, “name”: “John Doe”}}’

Here's an online demo!


Disclaimer: I've written fast-xml-parser

Fast XML Parser can help to convert XML to JSON and vice versa. Here is the example;

var options = {
    attributeNamePrefix : "@_",
    attrNodeName: "attr", //default is 'false'
    textNodeName : "#text",
    ignoreAttributes : true,
    ignoreNameSpace : false,
    allowBooleanAttributes : false,
    parseNodeValue : true,
    parseAttributeValue : false,
    trimValues: true,
    decodeHTMLchar: false,
    cdataTagName: "__cdata", //default is 'false'
    cdataPositionChar: "\\c",
};
if(parser.validate(xmlData)=== true){//optional
    var jsonObj = parser.parse(xmlData,options);
}

If you want to parse JSON or JS object into XML then

//default options need not to set
var defaultOptions = {
    attributeNamePrefix : "@_",
    attrNodeName: "@", //default is false
    textNodeName : "#text",
    ignoreAttributes : true,
    encodeHTMLchar: false,
    cdataTagName: "__cdata", //default is false
    cdataPositionChar: "\\c",
    format: false, 
    indentBy: "  ",
    supressEmptyNode: false
};
var parser = new parser.j2xParser(defaultOptions);
var xml = parser.parse(json_or_js_obj);

Here' a good tool from a documented and very famous npm library that does the xml <-> js conversions very well: differently from some (maybe all) of the above proposed solutions, it converts xml comments also.

var obj = {name: "Super", Surname: "Man", age: 23};

var builder = new xml2js.Builder();
var xml = builder.buildObject(obj);

I was using xmlToJson just to get a single value of the xml.
I found doing the following is much easier (if the xml only occurs once..)

let xml =
'<person>' +
  ' <id>762384324</id>' +
  ' <firstname>Hank</firstname> ' +
  ' <lastname>Stone</lastname>' +
'</person>';

let getXmlValue = function(str, key) {
  return str.substring(
    str.lastIndexOf('<' + key + '>') + ('<' + key + '>').length,
    str.lastIndexOf('</' + key + '>')
  );
}


alert(getXmlValue(xml, 'firstname')); // gives back Hank


In 6 simple ES6 lines:

xml2json = xml => {                                                                                                                                                     
  var el = xml.nodeType === 9 ? xml.documentElement : xml                                                                                                               
  var h  = {name: el.nodeName}                                                                                                                                          
  h.content    = Array.from(el.childNodes || []).filter(e => e.nodeType === 3).map(e => e.textContent).join('').trim()                                                  
  h.attributes = Array.from(el.attributes || []).filter(a => a).reduce((h, a) => { h[a.name] = a.value; return h }, {})                                                 
  h.children   = Array.from(el.childNodes || []).filter(e => e.nodeType === 1).map(c => h[c.nodeName] = xml2json(c))                                                    
  return h                                                                                                                                                              
}  

Test with echo "xml2json_example()" | node -r xml2json.es6 with source at https://github.com/brauliobo/biochemical-db/blob/master/lib/xml2json.es6


The best way to do it using server side as client side doesn't work well in all scenarios. I was trying to build online json to xml and xml to json converter using javascript and I felt almost impossible as it was not working in all scenarios. Ultimately I ended up doing it server side using Newtonsoft in ASP.MVC. Here is the online converter http://techfunda.com/Tools/XmlToJson


I've created a recursive function based on regex, in case you don't want to install library and understand the logic behind what's happening:

const xmlSample = '<tag>tag content</tag><tag2>another content</tag2><tag3><insideTag>inside content</insideTag><emptyTag /></tag3>';
console.log(parseXmlToJson(xmlSample));

function parseXmlToJson(xml) {
    const json = {};
    for (const res of xml.matchAll(/(?:<(\w*)(?:\s[^>]*)*>)((?:(?!<\1).)*)(?:<\/\1>)|<(\w*)(?:\s*)*\/>/gm)) {
        const key = res[1] || res[3];
        const value = res[2] && parseXmlToJson(res[2]);
        json[key] = ((value && Object.keys(value).length) ? value : res[2]) || null;

    }
    return json;
}

Regex explanation for each loop:

  • res[0] - return the xml (as is)
  • res[1] - return the xml tag name
  • res[2] - return the xml content
  • res[3] - return the xml tag name in case the tag closes itself. In example: <tag />

You can check how the regex works here: https://regex101.com/r/ZJpCAL/1

Note: In case json has a key with an undefined value, it is being removed. That's why I've inserted null at the end of line 9.


You can also use txml. It can parse into a DOM made of simple objects and stringify. In the result, the content will be trimmed. So formating of the original with whitespaces will be lost. But this could be used very good to minify HTML.

const xml = require('txml');
const data = `
<tag>tag content</tag>
<tag2>another content</tag2>
<tag3>
  <insideTag>inside content</insideTag>
  <emptyTag />
</tag3>`;

const dom = xml(data); // the dom can be JSON.stringified

xml.stringify(dom); // this will return the dom into an xml-string

Disclaimer: I am the author of txml, the fastest xml parser in javascript.