Convert JSON to XML in JavaScript

JSON and XML have different data models, so there is no single universal conversion. Libraries make choices about roots, arrays, attributes, text nodes, nulls, and invalid XML element names; document those choices in APIs.

Quick Start#

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

Using xmlbuilder2#

1// npm install xmlbuilder22import { create } from "xmlbuilder2";34const data = { user: { name: "Ada", active: true } };5const xml = create({ version: "1.0" })6  .ele(data)7  .end({ prettyPrint: true });89console.log(xml);

Common Operations#

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

Define a root explicitly#

1const payload = { name: "Ada", roles: { role: ["admin", "editor"] } };2const xml = create({ version: "1.0" })3  .ele({ response: payload })4  .end({ prettyPrint: true });

Important Notes#

Treat the JSON-to-XML mapping as part of your API contract; different libraries represent arrays and attributes differently.

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#

• RFC 8259: JSON
• W3C XML
• MDN JavaScript