libxml2-wasm

libxml2-wasm

Why another xml lib?

Comparing to the previous two main approaches, pure javascript implementation as well as traditional C implementation binding, using WebAssembly combines the pros from both sides, providing good performance while keeping best compatibility with modern Javascript runtime.

	Javascript Implementation	Traditional C Binding	WebAssembly
Parsing Speed1	Average	Fast	Fast
C/C++ Toolchain	Not required	Required2	Not Required
Prebuilt Binaries	N/A	One for each OS/Runtime version	Universal for all OS/Runtime versions
Prebuilt Binary Compatibility	N/A	May broke across libc versions	Very Good
Browser Compatibility	Yes	No	Yes

Documentation

https://jameslan.github.io/libxml2-wasm/index.html

Supported Environments

Due to the usage of WebAssembly, ES module and top level await etc, it requires the minimum version of the following environments,

Environment	Version
Node.js	v16+
Chrome	V89+
Edge	V89+
Safari	v15+

Features

• Parsing
• Validating
• XInclude and XSD include/import (experimental)

Getting started

Install libxml2-wasm package:

npm i libxml2-wasm

libxml2-wasm is an ES module, importing it are different between ES module and commonJS module.

ESM

Import it directly.

import fs from 'node:fs';
import { XmlDocument } from 'libxml2-wasm';
const doc1 = XmlDocument.fromString('<note><to>Tove</to></note>');
const doc2 = XmlDocument.fromBuffer(fs.readFileSync('doc.xml'));
doc1.dispose();
doc2.dispose();

CommonJS

Dynamic import is needed:

const fs = require('node:fs');
import('libxml2-wasm').then(({ XmlDocument }) => {
    const doc1 = XmlDocument.fromString('<note><to>Tove</to></note>');
    const doc2 = XmlDocument.fromBuffer(fs.readFileSync('doc.xml'));
    doc1.dispose();
    doc2.dispose();
});

IMPORTANT: dispose() is required to avoid memory leak.

For more detail, see the Doc.

Footnotes

• The speed of different libraries varies a lot, see benchmark. ↩

• The requirement of C/C++ toolchain may be waived if prebuilt binary is available. ↩