libexpat XML SAX parser binding for node.js
384
stars
254
commits
JavaScript
primary language
Jan 21, 2026
updated
README
node-expat
Motivation
You use Node.js for speed? You process XML streams? Then you want the fastest XML parser: libexpat!
Install
npm install node-expat
Usage
Important events emitted by a parser:
(function () {
"use strict";
var expat = require('node-expat')
var parser = new expat.Parser('UTF-8')
parser.on('startElement', function (name, attrs) {
console.log(name, attrs)
})
parser.on('endElement', function (name) {
console.log(name)
})
parser.on('text', function (text) {
console.log(text)
})
parser.on('error', function (error) {
console.error(error)
})
parser.write('<html><head><title>Hello World</title></head><body><p>Foobar</p></body></html>')
}())
API
#on('startElement' function (name, attrs) {})#on('endElement' function (name) {})#on('text' function (text) {})#on('processingInstruction', function (target, data) {})#on('comment', function (s) {})#on('xmlDecl', function (version, encoding, standalone) {})#on('startCdata', function () {})#on('endCdata', function () {})#on('entityDecl', function (entityName, isParameterEntity, value, base, systemId, publicId, notationName) {})#on('error', function (e) {})#stop()pauses#resume()resumes
Error handling
We don't emit an error event because libexpat doesn't use a callback
either. Instead, check that parse() returns true. A descriptive
string can be obtained via getError() to provide user feedback.
Alternatively, use the Parser like a node Stream. write() will emit
error events.
Namespace handling
A word about special parsing of xmlns: this is not necessary in a bare SAX parser like this, given that the DOM replacement you are using (if any) is not relevant to the parser.
Benchmark
npm run benchmark
| module | ops/sec | native | XML compliant | stream |
|---|---|---|---|---|
| sax-js | 99,412 | ☐ | ☑ | ☑ |
| node-xml | 130,631 | ☐ | ☑ | ☑ |
| libxmljs | 276,136 | ☑ | ☑ | ☐ |
| node-expat | 322,769 | ☑ | ☑ | ☑ |
Higher is better.
Testing
npm install -g standard
npm test
Windows
If you fail to install node-expat as a dependency of node-xmpp, please update node-xmpp as it doesn't use node-expat anymore.
Dependencies for node-gyp https://github.com/TooTallNate/node-gyp#installation
See https://github.com/astro/node-expat/issues/78 if you are getting errors about not finding nan.h.
expat.vcproj
VCBUILD : error : project file 'node-expat\build\deps\libexpat\expat.vcproj' was not found or not a valid proj
ect file. [C:\Users\admin\AppData\Roaming\npm\node_modules\node-expat\build\bin
ding.sln]
Install Visual Studio C++ 2012 and run npm with the --msvs_version=2012 flag.
Contributors
Similar repos
Languages
JavaScript
55.0%
C++
44.1%
libexpat XML SAX parser binding for node.js
384
stars
254
commits
JavaScript
primary language
Jan 21, 2026
updated
README
node-expat
Motivation
You use Node.js for speed? You process XML streams? Then you want the fastest XML parser: libexpat!
Install
npm install node-expat
Usage
Important events emitted by a parser:
(function () {
"use strict";
var expat = require('node-expat')
var parser = new expat.Parser('UTF-8')
parser.on('startElement', function (name, attrs) {
console.log(name, attrs)
})
parser.on('endElement', function (name) {
console.log(name)
})
parser.on('text', function (text) {
console.log(text)
})
parser.on('error', function (error) {
console.error(error)
})
parser.write('<html><head><title>Hello World</title></head><body><p>Foobar</p></body></html>')
}())
API
#on('startElement' function (name, attrs) {})#on('endElement' function (name) {})#on('text' function (text) {})#on('processingInstruction', function (target, data) {})#on('comment', function (s) {})#on('xmlDecl', function (version, encoding, standalone) {})#on('startCdata', function () {})#on('endCdata', function () {})#on('entityDecl', function (entityName, isParameterEntity, value, base, systemId, publicId, notationName) {})#on('error', function (e) {})#stop()pauses#resume()resumes
Error handling
We don't emit an error event because libexpat doesn't use a callback
either. Instead, check that parse() returns true. A descriptive
string can be obtained via getError() to provide user feedback.
Alternatively, use the Parser like a node Stream. write() will emit
error events.
Namespace handling
A word about special parsing of xmlns: this is not necessary in a bare SAX parser like this, given that the DOM replacement you are using (if any) is not relevant to the parser.
Benchmark
npm run benchmark
| module | ops/sec | native | XML compliant | stream |
|---|---|---|---|---|
| sax-js | 99,412 | ☐ | ☑ | ☑ |
| node-xml | 130,631 | ☐ | ☑ | ☑ |
| libxmljs | 276,136 | ☑ | ☑ | ☐ |
| node-expat | 322,769 | ☑ | ☑ | ☑ |
Higher is better.
Testing
npm install -g standard
npm test
Windows
If you fail to install node-expat as a dependency of node-xmpp, please update node-xmpp as it doesn't use node-expat anymore.
Dependencies for node-gyp https://github.com/TooTallNate/node-gyp#installation
See https://github.com/astro/node-expat/issues/78 if you are getting errors about not finding nan.h.
expat.vcproj
VCBUILD : error : project file 'node-expat\build\deps\libexpat\expat.vcproj' was not found or not a valid proj
ect file. [C:\Users\admin\AppData\Roaming\npm\node_modules\node-expat\build\bin
ding.sln]
Install Visual Studio C++ 2012 and run npm with the --msvs_version=2012 flag.
Similar repos
Contributors
Languages
JavaScript
55.0%
C++
44.1%