xml-lexer

Simple JavaScript Lexer for XML documents

Features

• Very small, fast and simple! (~250 sloc)
• Event driven API (SAX-like)
• Works in Browser, WebWorkers, ServiceWorkers, Node.js or React Native
• Fault tolerant
• Handles CDATA
• Easy to extend and fine tune (state machine is exposed in Lexer instances)

If you are looking for a XML Reader/Parser to convert XML documents into Javascript objects, check my other projects:

• xml-reader
• xml-query

Install

npm install --save xml-lexer

Examples

Happy case

const lexer = require('xml-lexer').create();

const xml =
`<hello color="blue">
  <greeting>Hello, world!</greeting>
</hello>`;

lexer.on('data', (data) => console.log(data));
lexer.write(xml);

/*
Console output:

{ type: 'open-tag', value: 'hello' }
{ type: 'attribute-name', value: 'color' }
{ type: 'attribute-value', value: 'blue' }
{ type: 'open-tag', value: 'greeting' }
{ type: 'data', value: 'Hello, world!' }
{ type: 'close-tag', value: 'greeting' }
{ type: 'close-tag', value: 'hello' }
*/

Chunked processing

const lexer = require('xml-lexer').create();

const chunk1 = `<hello><greet`; // note this
const chunk2 = `ing>Hello, world!</greeting></hello>`;

lexer.on('data', (data) => console.log(data));
lexer.write(chunk1);
lexer.write(chunk2);

/*
Console output:

{ type: 'open-tag', value: 'hello' }
{ type: 'open-tag', value: 'greeting' }
{ type: 'data', value: 'Hello, world!' }
{ type: 'close-tag', value: 'greeting' }
{ type: 'close-tag', value: 'hello' }
*/

Document with errors

const lexer = require('xml-lexer').create();

lexer.on('data', (data) => console.log(data));
lexer.write(`<<hello">hi</hello attr="value">`);

/*
Console output (note the open-tag value):

{ type: 'open-tag', value: '<hello"' }
{ type: 'data', value: 'hi' }
{ type: 'close-tag', value: 'hello' }
*/

Update state machine to fix document errors

const Lexer = require('xml-lexer');
const lexer = Lexer.create();

lexer.stateMachine[Lexer.State.tagBegin][Lexer.Action.lt] = () => {};
lexer.stateMachine[Lexer.State.tagName][Lexer.Action.error] = () => {};

lexer.on('data', (data) => console.log(data));
lexer.write(`<<hello">hi</hello attr="value">`);

/*
Console output (note the fixed open-tag value):

{ type: 'open-tag', value: 'hello' }
{ type: 'data', value: 'hi' }
{ type: 'close-tag', value: 'hello' }
*/

License

MIT