Convert XML to JSON in JavaScript — Clean, Lightweight & Customizable

🔄 Convert XML to JSON in JavaScript (Without External Libraries)

When you’re dealing with integrations in NetSuite or Boomi (or building a mobile app like I once did), you’ll often hit a wall:

“Why is this API returning only XML? I just need a clean JSON object!”

That’s exactly the issue I ran into — and after testing dozens of solutions, I found a clean, developer-tested function that converts any XML DOM object into JSON — no 3rd party library needed.

Let’s break it down — I’ll explain how it works, common fixes, and how you can use it in real-world NetSuite or JavaScript projects.

🧠 The XML to JSON Function

Here’s a battle-tested XML-to-JSON function that handles:

• Attributes
• Nested child elements
• Text and CDATA nodes
• Arrays (multiple same-tag children)

function xmlToJson(xml) {
  var obj = {};

  if (xml.nodeType === 1) { // ELEMENT_NODE
    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_NODE
    obj = xml.nodeValue.trim();
  } else if (xml.nodeType === 4) { // CDATA_SECTION_NODE
    obj = xml.data;
  }

  // Recursively process child nodes
  if (xml.hasChildNodes()) {
    for (var i = 0; i < xml.childNodes.length; i++) {
      var item = xml.childNodes.item(i);
      var nodeName = item.nodeName;
      var child = xmlToJson(item);

      if (child === "") continue;

      if (typeof(obj[nodeName]) === "undefined") {
        obj[nodeName] = child;
      } else {
        if (!Array.isArray(obj[nodeName])) {
          obj[nodeName] = [obj[nodeName]];
        }
        obj[nodeName].push(child);
      }
    }
  }

  return obj;
}

⚙️ Example: Convert and Log XML to JSON

// Parse XML string into DOM
var xmlStr = `<person><name>David</name><age>35</age></person>`;
var xmlDoc = new DOMParser().parseFromString(xmlStr, "text/xml");

// Convert to JSON
var jsonObj = xmlToJson(xmlDoc);
console.log(JSON.stringify(jsonObj, null, 2));

Output:

{
  "person": {
    "name": "David",
    "age": "35"
  }
}

🛠️ Common Fixes for Real-World Use

Here are the most common issues developers ran into — and how the community improved the function:

✅ Fix #1: Attributes Handling

Many early versions used xml.attributes[j] — but that caused crashes in some browsers.
✅ Fix: Use xml.attributes.item(j) for better compatibility.

✅ Fix #2: Empty Text Nodes

Whitespace-only text nodes can clutter your JSON.
✅ Fix: Add trim() and skip blank nodes.

✅ Fix #3: Arrays vs. Objects

When an element repeats, we need an array.
✅ Fix: Use this check:

if (!Array.isArray(obj[nodeName])) {
  obj[nodeName] = [obj[nodeName]];
}

✅ Fix #4: CDATA Support

Some XML includes CDATA tags.
✅ Fix: Add a check for nodeType === 4.

🔗 NetSuite Use Case: Convert XML Response in SuiteScript

In SuiteScript, sometimes external REST APIs return XML instead of JSON. With this function, you can:

• Convert the XML response to a usable JSON object
• Traverse nodes easily
• Store or transform into NetSuite records

Example inside a RESTlet or Map/Reduce script:

var response = https.get({ url: myApiUrl });
var xmlDoc = xml.Parser.fromString({ text: response.body, format: xml.Parser.Type.XML });
var jsonObj = xmlToJson(xmlDoc);

🔗 Related Guides on The NetSuite Pro

• 🔄 Using Saved Searches in Scripts
• 🧪 Debugging & Logging in SuiteScript
• 🧰 JSON/XML Parsing

💡 Final Thoughts: Keep This Function Handy

Whether you’re parsing RSS feeds, integrating 3PL data, or just cleaning up XML responses from legacy APIs — this little xmlToJson() function is pure gold.

✅ No libraries
✅ Customizable
✅ Works in browser, Node.js, SuiteScript, or Boomi JavaScript components