libexpat XML SAX parser binding for node.js
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You use node.js for speed? You process XML streams? Then you want the fastest XML parser: libexpat!


A stupid speed test is supplied in bench.js. We measure how many 25-byte elements a SAX parser can process:

  • node-xml (pure JavaScript): 23,000 el/s
  • libxmljs (libxml2 binding): 77,000 el/s
  • node-expat (libexpat binding, this): 113,000 el/s

These numbers were recorded on a Core 2 2400 MHz and may turn out to be bullshit, given my few node.js experience.


node-waf configure
node-waf build

For using the library, make sure build/default/expat.node is in either $NODE_PATH or require.paths.

Important events emitted by a parser:

  • startElement with name, attrs
  • endElement with name
  • text with string

There are more. Use test.js for reference.

It's possible to stop and resume the parser from within element handlers using the parsers stop() and resume() methods.

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.

Namespace handling

A word about special parsing of xmlns: this is not neccessary in a bare SAX parser like this, given that the DOM replacement you are using (if any) is not relevant to the parser.