Convert XML to JSON in TypeScript

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 TypeScript API or a widely used package for this task.

Using xml2js#

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

Common Operations#

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

Typed boundary#

1const value: unknown = await parseStringPromise(xml, { explicitArray: false });2// Validate/narrow `value` before treating it as a domain object.

Important Notes#

XML parser output is runtime data; TypeScript interfaces do not validate it. Narrow or schema-validate before use.

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
• TypeScript Handbook