Convert XML to JSON in JavaScript

XML can represent attributes, mixed text, namespaces, repeated elements, and ordering in ways JSON cannot represent directly. Pick a library and a stable mapping convention, then test it with real documents.

Quick Start#

The following example uses the standard JavaScript API or a widely used package for this task.

Using xml2js#

1// npm install xml2js2import { parseStringPromise } from "xml2js";34const value = await parseStringPromise(xml, {5  explicitArray: false,6  trim: true,7});89const json = JSON.stringify(value, null, );10console.log(json);

Common Operations#

This second pattern covers a common production operation or a safer way to handle real input.

Keep attributes explicit#

1const value = await parseStringPromise(xml, {2  explicitArray: false,3  attrkey: "@",4  charkey: "#text",5});

Important Notes#

Choose and document attribute/text keys. Never assume an XML-to-JSON conversion is perfectly reversible without a defined mapping.

Best Practices#

1. Treat external input as untrusted and handle parse/validation errors explicitly.
2. Keep encoding, units, formats, and library-specific mapping rules explicit at system boundaries.
3. Add test vectors that cover empty input, Unicode text, malformed input, and representative production data.

References#

• W3C XML
• RFC 8259: JSON
• MDN JavaScript