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Convert Unity3D json to Javascript Object json format

My whole workflow:
Unity3D(encoding class data in json format) -> WebGL Build -> Javascript html -> Socket.IO
Those data type(int, byte[], string) should be readable in socket.io.
This is the function I used in Unity3D, in order to convert a class to json string.
JsonUtility.ToJson();
When I print in node.js, I got this and it couldn't understand the data type.
{"Type":0,"Str":"AAA","Byte":[0]}
If it's correct, I will get below result when I print in node.js.
{ Type: 0, Str: 'AAA', Byte: [ 0 ] }
Thus, I need a solution to convert them.
Could someone please tell me the easiest way to convert them in C#?
UPDATE: more info
Below C# script is working in Unity3D, and I want to convert this:
Application.ExternalEval(#"
if(typeof window.socketIO !== 'undefined')
{
window.socketIO.emit('" + e + #"', " + data + #");
}
");
https://docs.unity3d.com/Manual/webgl-interactingwithbrowserscripting.html
Because "Application.ExternalEval" is depreciated in latest Unity, I need to convert them into something like this:
mergeInto(LibraryManager.library, {
WebSocketEmitData: function (_e, _data) {
var e = Pointer_stringify(_e);
var data = Pointer_stringify(_data);
if(typeof window.socketIO !== 'undefined')
{
window.socketIO.emit(e, data);
}
}
});
Thanks!

I use Javascript/Unity/C# heavily on my current project, I strongly advice you to use JSON.NET For Unity it will emit a universal json format, that is similar to the one on the javascript JSON class.
Usage pretty similar to unity's primitive json utility.
JsonUtility.ToJson => JsonConvert.SerializeObject
JsonUtility.FromJson => JsonConvert.DeserializeObject<T>
That being said, let's convert a json string from the C# object to a javascript object.
// Convert your json string to a native javascript object.
var jsObject = JSON.parse(str);
console.log(jsObject.Type); // outputs 0
console.log(jsObject.Byte.length); // outputs 1
console.log(jsObject.Str); // outputs AAA
// Convert your native javascript object to another of certain type,
// will assume the desired javascript type is Player in a namespace Database
var player = Object.assign(new Database.Player(), jsObject);
Also instead of if(typeof window.socketIO !== 'undefined') use if(typeof window.socketIO) it is cleaner, checks for both null and undefined.

Finally I found the answers myself. I didn't notice that I can emit object instead of string message. and now it works!
WebSocketEmitData: function (_e, _data) {
var e = Pointer_stringify(_e);
var data = Pointer_stringify(_data);
var obj = JSON.parse(data);
if(typeof window.socketIO !== 'undefined')
{
window.socketIO.emit(e, obj);
}
}

Why JSON.stringify($('#calendar').fullcalendar('clientEvents')) fails?

As title, when I try to do:
myString = JSON.stringify($('#calendar').fullcalendar('clientEvents'));
it fails. I tried to alert myString but I see a series of [Object object], ... . But if i try to alert myArray[0].title for example, it returns correctly.
Where I'm doing wrong?
P.S. The goal is to obtain a string to save on a file via AJAX.

Your results tell you that the objects in the array that the fullCalendar clientEvents method gives you can't be directly converted to JSON. I get slightly different results on the http://fullcalendar.io page (I get an error about trying to convert a circular structure); I assume that's down to differences either in the FullCalendar version you're using vs. they're using, or differences in how your browser and mine deal with circular structures. Either way, the objects apparently can't be used as-is.
The goal is to obtain a string to save on a file via AJAX.
You can do that by using map on the array to get objects that can be converted to JSON successfully, whitelisting the properties you want (or blacklisting the ones you don't want).
Here's an example whitelisting the start, end, and title properties:
var json = JSON.stringify($("#calendar").fullCalendar("clientEvents").map(function(e) {
return {
start: e.start,
end: e.end,
title: e.title
};
}));
Heres one blacklisting source and any property starting with _:
var json = JSON.stringify($("#calendar").fullCalendar("clientEvents").map(function(e) {
var rv = {};
Object.keys(e)
.filter(function(k) {
return k != "source" && !k.startsWith("_");
})
.forEach(function(k) {
rv[k] = e[k];
});
return rv;
}));
...which worked for me on their site.
Here are ES2015 versions of both of those:
Whitelisting:
let json = JSON.stringify($("#calendar").fullCalendar("clientEvents").map(e => ({
start: e.start,
end: e.end,
title: e.title
})));
Blacklisting:
let json = JSON.stringify($("#calendar").fullCalendar("clientEvents").map(e => {
let rv = {};
Object.keys(e)
.filter(k => k != "source" && !k.startsWith("_"))
.forEach(k => {
rv[k] = e[k];
});
return rv;
}));

Convert xml to json in javascript or d3.js [duplicate]

How would you convert from XML to JSON and then back to XML?
The following tools work quite well, but aren't completely consistent:
xml2json
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.

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.

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

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.

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.

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

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 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!

There is an open sourced library Xml-to-json with methods jsonToXml(json) and xmlToJson(xml).
Here's an online demo!

This function directly reads the DOM properties of the XMLDocument (or document node/element) to build the JSON completely and accurately without trying to guess or match. Pass it responseXML, not responseText from XMLHttpRequest.
xml2json(xmlDoc)
If you only have a string of XML and not an XMLDocument, jQuery will convert your text to one.
xml2json($(xmlString)[0])
Each node becomes an object. (All elements are nodes, not all nodes are elements (e.g. text within an element).)
Every object contains the node name and type.
If it has attributes, they appear as properties in an attributes object.
If it has children, they appear recursively as node->objects in a children array.
If it's a Text, CDATA, or Comment node (bare text between element tags) or a comment, it shouldn't have attributes or children but the text will be in a text property.
{
// Always present
"name": "FancyElement",
"type": "Element",
// If present
"attributes: {
"attr1": "val1",
"attr2": "val2"
},
"children": [...],
"text": "buncha fancy words"
}
Caveat: I'm not familiar with all the node types. It's probably not grabbing needed/useful info from all of them. It was tested on and behaves as expected for
Element
Text
CDATA
Comment
Document
function xml2json(xml) {
try {
const types = [null,
"Element",
"Attribute",
"Text",
"CDATA",
"EntityReference", // Deprecated
"Entity", // Deprecated
"ProcessingInstruction",
"Comment",
"Document",
"DocumentType",
"DocumentFragment",
"Notation" // Deprecated
];
var o = {};
o.name = xml.nodeName;
o.type = types[xml.nodeType];
if (xml.nodeType == 3 ||
xml.nodeType == 4 ||
xml.nodeType == 8 ) {
o.text = xml.textContent;
} else {
if (xml.attributes) {
o.attributes = {};
for (const a of xml.attributes) {
o.attributes[a.name] = a.value;
}
}
if (xml.childNodes.length) {
o.children = [];
for (const x of xml.childNodes) {
o.children.push(xml2json(x))
}
}
}
return (o);
} catch (e) {
alert('Error in xml2json. See console for details.');
console.log('Error in xml2json processing node:');
console.log(o);
console.log('Error:');
console.log(e);
}
}
var doc = document.getElementById("doc");
var out = document.getElementById("out");
out.innerText = JSON.stringify(xml2json(doc), null, 2);
/* Let's process the whole Code Snippet #document, why not?
* Yes, the JSON we just put in the document body and all
* this code is encoded in the JSON in the console.
* In that copy you can see why the XML DOM will all be one line.
* The JSON in the console has "\n" nodes all throughout.
*/
console.log(xml2json(document));
#doc,
#out {
border: 1px solid black;
}
<div id="doc"><!-- The XML DOM will all be on one line --><div personality="bubbly" relevance=42>This text is valid for HTML.<span>But it probably shouldn't be siblings to an element in XML.</span></div></div>
<pre id="out"></pre>

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

Parse JSON string to JavaScript object with function name

I have a JSON string stored in a data attribute.
{
"active": true,
"icons": {
"activeHeader": "ui-icon-alert"
},
"animate": {
"duration": 1000,
"always": dMethod
}
}
And I have a function which named dMethod:
function dMethod() {
alert("DONE");
}
When I try to parse the string via JSON.parse I get an error said invalid character. I check and the dMethod is defined when the parse method was running and if I removed the ,"always":dMethod part then the parser worked correctly.
I can't use quotation marks around the dMethod because then the type will be string type instead of object function.
Any help would be appreciated.
Thanks,
Péter
EDIT:
Thanks you for all the answers. I make some clarification so maybe better you understand the problem. I make a really simple js library to make jqueryui unobstructive:
var juiObjects = ["accordion", "autocomplete", "button", "datepicker", "dialog", "menu", "progressbar", "slider", "spinner", "tabs", "tooltip"];
$(document).ready(function() {
for (var i = 0; i < juiObjects.length; i++) {
var attributeName = "data-" + juiObjects[i];
$("["+ attributeName + "]").each(function () {
var optionsValue = $(this).attr(attributeName);
var options = JSON.parse(optionsValue);
$(this)[juiObjects[i]](options);
});
}
});
I had to choice between JSON.parse and eval. But I think eval wouldn't be so good choice. And try to keep the "library" as simple as possible. But it looks like I have sparete the code along the widgets.

Functions are not valid data types in JSON (see http://en.wikipedia.org/wiki/JSON#Data_types.2C_syntax_and_example).
I think you have to deserialize it as a string, then post-process your object and set "always" to your method.

It can be done by quoting the dMethod, by executing the function on the window object using the [] syntax:
function dMethod() {
alert("DONE");
}
var json = '{"active":true,"icons":{"activeHeader":"ui-icon-alert"},"animate":{"duration":1000,"always":"dMethod"}}'; // quoted
var obj = JSON.parse(json);
window[obj.animate.always]();

JSON.parse expects a valid JSON string. So, if you want to use it you should quote the dMethod function. Isn't it possible to replace the string "dMethod" with the real function after the parsing.

You can't parse that string as JSON, because it's not valid JSON.
You can turn the string into an object by executing it using the eval function, but of course the usual warnings about executing anything dynamically applies. If you don't have full control over what's in the string, it might be possible to use for cross site scripting.
var obj = eval(json);
obj.always();

This is how to serialize object with its functions:
JSON.stringify(YOUR_OBJECT, function (key, value) {
if (typeof value === 'function') {
return value.toString();
}
return value;
});
and this is how to deserialize it back:
JSON.parse(YOUR_JSON_STRING, function (key, value) {
if (value
&& typeof value === "string"
&& value.substr(0,8) == "function") {
var startBody = value.indexOf('{') + 1;
var endBody = value.lastIndexOf('}');
var startArgs = value.indexOf('(') + 1;
var endArgs = value.indexOf(')');
return new Function(value.substring(startArgs, endArgs)
, value.substring(startBody, endBody));
}
return value;
});

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:
xml2json
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.

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.

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

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.

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.

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

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 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!

There is an open sourced library Xml-to-json with methods jsonToXml(json) and xmlToJson(xml).
Here's an online demo!

This function directly reads the DOM properties of the XMLDocument (or document node/element) to build the JSON completely and accurately without trying to guess or match. Pass it responseXML, not responseText from XMLHttpRequest.
xml2json(xmlDoc)
If you only have a string of XML and not an XMLDocument, jQuery will convert your text to one.
xml2json($(xmlString)[0])
Each node becomes an object. (All elements are nodes, not all nodes are elements (e.g. text within an element).)
Every object contains the node name and type.
If it has attributes, they appear as properties in an attributes object.
If it has children, they appear recursively as node->objects in a children array.
If it's a Text, CDATA, or Comment node (bare text between element tags) or a comment, it shouldn't have attributes or children but the text will be in a text property.
{
// Always present
"name": "FancyElement",
"type": "Element",
// If present
"attributes: {
"attr1": "val1",
"attr2": "val2"
},
"children": [...],
"text": "buncha fancy words"
}
Caveat: I'm not familiar with all the node types. It's probably not grabbing needed/useful info from all of them. It was tested on and behaves as expected for
Element
Text
CDATA
Comment
Document
function xml2json(xml) {
try {
const types = [null,
"Element",
"Attribute",
"Text",
"CDATA",
"EntityReference", // Deprecated
"Entity", // Deprecated
"ProcessingInstruction",
"Comment",
"Document",
"DocumentType",
"DocumentFragment",
"Notation" // Deprecated
];
var o = {};
o.name = xml.nodeName;
o.type = types[xml.nodeType];
if (xml.nodeType == 3 ||
xml.nodeType == 4 ||
xml.nodeType == 8 ) {
o.text = xml.textContent;
} else {
if (xml.attributes) {
o.attributes = {};
for (const a of xml.attributes) {
o.attributes[a.name] = a.value;
}
}
if (xml.childNodes.length) {
o.children = [];
for (const x of xml.childNodes) {
o.children.push(xml2json(x))
}
}
}
return (o);
} catch (e) {
alert('Error in xml2json. See console for details.');
console.log('Error in xml2json processing node:');
console.log(o);
console.log('Error:');
console.log(e);
}
}
var doc = document.getElementById("doc");
var out = document.getElementById("out");
out.innerText = JSON.stringify(xml2json(doc), null, 2);
/* Let's process the whole Code Snippet #document, why not?
* Yes, the JSON we just put in the document body and all
* this code is encoded in the JSON in the console.
* In that copy you can see why the XML DOM will all be one line.
* The JSON in the console has "\n" nodes all throughout.
*/
console.log(xml2json(document));
#doc,
#out {
border: 1px solid black;
}
<div id="doc"><!-- The XML DOM will all be on one line --><div personality="bubbly" relevance=42>This text is valid for HTML.<span>But it probably shouldn't be siblings to an element in XML.</span></div></div>
<pre id="out"></pre>

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