Convert XML to JSON (and back) using Javascript

Question

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

Answer 1

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 contentanother contentinside content';
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:

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.