Introduction to Node Expat

Node Expat is a Node.js binding for the Expat XML Parser Library. It is a fast XML parser that uses the Expat library to provide high-performance XML parsing in Node.js applications.

Installing Node Expat

npm install node-expat

Basic Usage

Here is a basic example of how to use Node Expat to parse XML:

 const expat = require('node-expat'); const parser = new expat.Parser('UTF-8');
parser.on('startElement', function(name, attrs) {
  console.log('Start element:', name, attrs);
});
parser.on('endElement', function(name) {
  console.log('End element:', name);
});
parser.on('text', function(text) {
  console.log('Text:', text);
});
parser.parse('Hello World'); 

API Examples

startElement Event

This event is emitted when the parser encounters a start tag:

 parser.on('startElement', function (name, attrs) {
  console.log('Start element:', name, attrs);
}); 

endElement Event

This event is emitted when the parser encounters an end tag:

 parser.on('endElement', function (name) {
  console.log('End element:', name);
}); 

text Event

This event is emitted when the parser encounters text between tags:

 parser.on('text', function (text) {
  console.log('Text:', text);
}); 

error Event

This event is emitted when the parser encounters an error:

 parser.on('error', function (error) {
  console.error('Parsing error:', error);
}); 

Example Application

Here is a full example of a simple application that processes an XML file and logs the elements and text content to the console:

 const fs = require('fs'); const expat = require('node-expat');
const parser = new expat.Parser('UTF-8'); const xmlFile = 'example.xml';
parser.on('startElement', function(name, attrs) {
  console.log(`Start element: ${name}`, attrs);
});
parser.on('endElement', function(name) {
  console.log(`End element: ${name}`);
});
parser.on('text', function(text) {
  console.log(`Text: ${text}`);
});
parser.on('error', function(error) {
  console.error(`Parsing error: ${error}`);
});
fs.readFile(xmlFile, 'utf-8', function (err, data) {
  if (err) {
    console.error(`Error reading file: ${err}`);
    return;
  }
  if (!parser.parse(data)) {
    console.error(`Parsing error: ${parser.getError()}`);
  }
}); 

This example reads an XML file, processes it using Node Expat, and logs the details to the console.

Node Expat is a powerful tool for XML parsing in Node.js applications, providing a simple and efficient way to handle XML data.

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