The fast-xml-parser npm package is a fast and powerful XML parser and validator that can convert XML to a JavaScript object, JSON, or a traversable JS object. It can also convert a JS object to XML. It is designed to be very fast and efficient, and it provides various options to control the XML parsing and validation process.

What are fast-xml-parser's main functionalities?

XML to JSON Conversion

Converts XML data to a JSON object. The 'parse' function takes an XML string and optional options object, and returns a JSON representation of the XML.

const { parse } = require('fast-xml-parser');
const xmlData = '<note><to>User</to><from>Library</from><heading>Reminder</heading><body>Don't forget to subscribe.</body></note>';
const options = {};
const jsonObj = parse(xmlData, options);

JSON to XML Conversion

Converts a JSON object to an XML string. The 'j2xParser' constructor takes an options object, and the 'parse' method converts the JSON object to an XML string.

const { j2xParser } = require('fast-xml-parser');
const parser = new j2xParser({});
const jsonObj = { note: { to: 'User', from: 'Library', heading: 'Reminder', body: 'Don't forget to subscribe.' } };
const xmlData = parser.parse(jsonObj);

XML Validation

Validates the XML string. The 'validate' function checks if the given XML string is well-formed and returns a validation result.

const { validate } = require('fast-xml-parser');
const xmlData = '<note><to>User</to><from>Library</from></note>';
const validationResult = validate(xmlData);

Traversable Object Creation

Creates a traversable JavaScript object from XML. The 'XMLParser' constructor creates a parser instance, and the 'parse' method converts the XML string into a traversable JS object.

const { XMLParser } = require('fast-xml-parser');
const xmlData = '<note><to>User</to><from>Library</from></note>';
const parser = new XMLParser();
const traversableObject = parser.parse(xmlData);

Other packages similar to fast-xml-parser

fast-xml-parser

[![NPM quality][quality-image]][quality-url]

Validate XML, Parse XML to JS Object, or Build XML from JS Object without C/C++ based libraries and no callback.

I had recently published a book, The Power Glasses. Please have a look. Your feedback would be helpful. You can mail me for a free copy.

Sponsor this project

fxp_sponsors

Users

The list of users are mostly published by Github or communicated directly. Feel free to contact if you find any information wrong.

Main Features

Validate XML data syntactically
Parse XML to JS Object
Build XML from JS Object
Compatible to node js packages, in browser, and in CLI (click try me button above for demo)
Faster than any other pure JS implementation.
It can handle big files (tested up to 100mb).
Controlled parsing using various options
XML Entities, HTML entities, and DOCTYPE entites are supported.
unpaired tags (Eg <br> in HTML), stop nodes (Eg <script> in HTML) are supported.
You can restore almost same XML from JSON
Supports comments
It can preserve Order of tags in JS object
You can control if a single tag should be parsed into array.
Supports parsing of PI (Processing Instruction) tags with XML declaration tags
And many more other features.

v5

I developed v5 in Apr 2023. And I didn't get the chance to complete all the features. I've ensured that new features don't impact performance. With v5, you have more control on parsing output. Check docs for syntax help and basic understanding.

Please leave a comment in discussion forum for your suggestions and if you really need v5.

How to use

To use as package dependency $ npm install fast-xml-parser or $ yarn add fast-xml-parser

To use as system command $ npm install fast-xml-parser -g

To use it on a webpage include it from a CDN

Example

As CLI command

$ fxparser some.xml

In a node js project

const { XMLParser, XMLBuilder, XMLValidator} = require("fast-xml-parser");

const parser = new XMLParser();
let jObj = parser.parse(XMLdata);

const builder = new XMLBuilder();
const xmlContent = builder.build(jObj);

In a HTML page

<script src="path/to/fxp.min.js"></script>
:
<script>
  const parser = new fxparser.XMLParser();
  parser.parse(xmlContent);
</script>

Bundle size

Bundle Name	Size
fxbuilder.min.js	6.5K
fxparser.min.js	20K
fxp.min.js	26K
fxvalidator.min.js	5.7K

Documents

v3	v4	v5
documents	Getting Started XML Parser XML Builder XML Validator Entities HTML Document Parsing PI Tag processing	Getting Started Features Options Output Builders Value Parsers

note: version 5 is released with version 4 tfor experimental use. Based on it's demand, it'll be developed and the features can be different in final release.

Performance

negative means error

XML Parser

Y-axis: requests per second
X-axis: File size

XML Builder

* Y-axis: requests per second

Usage Trend

Usage Trend of fast-xml-parser

Supporters

Contributors

This project exists thanks to all the people who contribute. [Contribute].

Backers

Thank you to all our backers! 🙏 [Become a backer]

License

MIT License

Donate $5

Keywords

FAQs

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Package last updated on 03 Sep 2024

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