@jetstreamapp/simple-xml

A minimal, zero-dependency XML parser and builder. Built as a lightweight replacement for fast-xml-parser when you only need simple XML parsing and building — no DTD, no schema validation, no streaming, no complex entity processing.

100% browser compatible. No Node.js APIs.

Built with Claude Code

Why?

• Zero dependencies — nothing to audit, nothing to break
• Tiny footprint — ~300 lines of code total
• Browser compatible — works anywhere JavaScript runs
• Fast-xml-parser compatible output — same object shape, drop-in replacement for simple use cases

Installation

npm install @jetstreamapp/simple-xml

Quick Start

import { parse, build } from '@jetstreamapp/simple-xml';

// Parse XML to a JavaScript object
const result = parse('<root><name>hello</name><count>42</count></root>');
// { root: { name: 'hello', count: 42 } }

// Build XML from a JavaScript object
const xml = build({ root: { name: 'hello', count: 42 } });
// '<root><name>hello</name><count>42</count></root>'

API

parse(xml: string, options?: ParseOptions): Record<string, unknown>

Parses an XML string into a JavaScript object.

const result = parse(soapResponse, {
  trimValues: true,
  ignoreAttributes: false,
  removeNSPrefix: true,
  attributeNamePrefix: '@_',
  processEntities: false,
});

ParseOptions

| Option | Type | Default | Description | | --------------------- | --------- | ------- | -------------------------------------------------------- | | trimValues | boolean | true | Trim whitespace from text content | | ignoreAttributes | boolean | false | Skip attributes entirely | | removeNSPrefix | boolean | false | Strip namespace prefixes (soap:Body → Body) | | attributeNamePrefix | string | '@_' | Prefix prepended to attribute names in the output object | | parseTagValue | boolean | true | Coerce numeric/boolean text values to their JS types | | processEntities | boolean | true | Decode XML entities (& → &, < → <, etc.) | | maxDepth | number | 256 | Maximum nesting depth allowed. Throws if exceeded | | strict | boolean | false | Throw on malformed XML (unclosed, mismatched, or extra closing tags) |

build(obj: Record<string, unknown>, options?: BuildOptions): string

Builds an XML string from a JavaScript object.

const xml = build(
  {
    Package: {
      '@xmlns': 'http://soap.sforce.com/2006/04/metadata',
      types: [{ members: ['MyClass', 'OtherClass'], name: 'ApexClass' }],
      version: '50.0',
    },
  },
  { format: true, ignoreAttributes: false, attributeNamePrefix: '@' },
);

BuildOptions

| Option | Type | Default | Description | | --------------------- | --------- | ------- | ---------------------------------------------------------- | | format | boolean | false | Pretty-print with indentation | | ignoreAttributes | boolean | false | Skip attributes when building XML | | attributeNamePrefix | string | '@_' | Prefix used to identify attribute keys in the input object | | indentBy | string | ' ' | Indentation string used when format is true |

Output Shape

The parser produces the same object shape as fast-xml-parser:

• Single child element → value directly on parent: { parent: { child: 'value' } }
• Multiple same-name children → array: { parent: { item: ['a', 'b', 'c'] } }
• Attributes → prefixed keys: { element: { '@_id': '1', '#text': 'content' } }
• Text-only leaf → string/number/boolean value: { element: 'hello' }
• Empty/self-closing → empty string: { element: '' }

Supported XML Features

• Elements, attributes, text content
• Namespace prefix stripping
• CDATA sections
• Comments (skipped)
• Processing instructions (skipped)
• Self-closing tags
• XML declaration (skipped)
• XML entities: named (&, <, >, ", ') and numeric ({, {)

License

MIT