fast-xml-parser
Advanced tools
Validate XML or Parse XML to JS/JSON very fast without C/C++ based libraries
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.
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);xml2js is a similar npm package that provides XML to JavaScript object conversion. It includes options to customize the parsing process and supports builder options for converting back to XML. Compared to fast-xml-parser, xml2js may be slower but offers a more feature-rich API for handling complex XML structures.
xml-js is another npm package that converts XML text to a JavaScript object and vice versa. It can also convert XML to JSON and supports compact and non-compact modes. While fast-xml-parser focuses on speed, xml-js provides a more extensive set of conversion options.
libxmljs is a Node.js package that provides bindings to the libxml C library. It allows for parsing and serializing XML and includes XPath and XSLT support. It is different from fast-xml-parser in that it is a binding to a native library, which may offer performance benefits and additional XML processing features.
Validate XML, Parse XML to JS/JSON and vice versa, or parse XML to Nimn rapidly without C/C++ based libraries and no callback
To use it in NPM package install it first
$npm install fast-xml-parser or using yarn $yarn add fast-xml-parser
To use it from CLI Install it globally with -g option.
$npm install fast-xml-parser -g
To use it on a webpage include it from parser.js or directly from CDN
var fastXmlParser = require('fast-xml-parser');
var jsonObj = fastXmlParser.parse(xmlData);
//construct schema manually or with the help of schema builder
var nimndata = fastXmlParser.parseToNimn(xmlData,schema);
//or
var options = {
attributeNamePrefix : "@_",
attrNodeName: "attr", //default is 'false'
textNodeName : "#text",
ignoreAttributes : true,
ignoreNameSpace : false,
allowBooleanAttributes : false,
parseNodeValue : true,
parseAttributeValue : false,
trimValues: true,
cdataTagName: "__cdata", //default is 'false'
cdataPositionChar: "\\c",
attrValueProcessor: a => he.decode(a, {isAttributeValue: true}),//default is a=>a
tagValueProcessor : a => he.decode(a) //default is a=>a
};
if(fastXmlParser.validate(xmlData)=== true){//optional
var jsonObj = fastXmlParser.parse(xmlData,options);
}
//Intermediate obj
var tObj = fastXmlParser.getTraversalObj(xmlData,options);
var jsonObj = fastXmlParser.convertToJson(tObj,options);
//construct schema manually or with the help of schema builder
var nimndata = fastXmlParser.convertTonimn(tObj,schema,options);
OPTIONS :
To use from command line
$xml2js [-ns|-a|-c|-v|-V] <filename> [-o outputfile.json]
$cat xmlfile.xml | xml2js [-ns|-a|-c|-v|-V] [-o outputfile.json]
To use it on webpage
var result = parser.validate(xmlData);
if(result !== true) cnosole.log(result.err);
var jsonObj = parser.parse(xmlData);
var Parser = require("fast-xml-parser").j2xParser;
//default options need not to set
var defaultOptions = {
attributeNamePrefix : "@_",
attrNodeName: "@", //default is false
textNodeName : "#text",
ignoreAttributes : true,
cdataTagName: "__cdata", //default is false
cdataPositionChar: "\\c",
format: false,
indentBy: " ",
supressEmptyNode: false,
tagValueProcessor: a=> he.encode(a, { useNamedReferences: true}),// default is a=>a
attrValueProcessor: a=> he.encode(a, {isAttributeValue: isAttribute, useNamedReferences: true})// default is a=>a
};
var parser = new Parser(defaultOptions);
var xml = parser.parse(json_or_js_obj);
OPTIONS :
With the correct options, you can get the almost original XML without losing any information.
when format is set to truetrue, tags with no value (text or nested tags) are written as self closing tags.We've compared various libraries which transforms XML to JS. Most of them either are dependent on C/C++ libraries, or slow, or don't do reverse transformation.
Why not C/C++ based libraries? C/C++ based libraries are no doubt faster than this library but they don't run in browser, and a user need to install extra supporting libraries on their computer.
| file size | fxp 3.0 validator (rps) | fxp 3.0 parser (rps) | xml2js 0.4.19 (rps) |
|---|---|---|---|
| 1.5k | 16581.06758 | 14032.09323 | 4615.930805 |
| 1.5m | 14918.47793 | 13.23366098 | 5.90682005 |
| 13m | 1.834479235 | 1.135582008 | -1 |
| 1.3k with CDATA | 30583.35319 | 43160.52342 | 8398.556349 |
| 1.3m with CDATA | 27.29266471 | 52.68877009 | 7.966000795 |
| 1.6k with cdata,prolog,doctype | 27690.26082 | 41433.98547 | 7872.399268 |
| 98m | 0.08473858148 | 0.2600104004 | -1 |
| file size | fxp 3.2 js to xml | xml2js 0.4.19 builder |
|---|---|---|
| 1.3k | 160148.9801 | 10384.99401 |
| 1.1m | 173.6374831 | 8.611884025 |
निम्न (NIMN) : Schema aware object compression. 60% more compressed than JSON. 40% more compressed than msgpack.
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This project exists thanks to all the people who contribute. [Contribute].
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FAQs
Validate XML, Parse XML, Build XML without C/C++ based libraries
The npm package fast-xml-parser receives a total of 24,137,726 weekly downloads. As such, fast-xml-parser popularity was classified as popular.
We found that fast-xml-parser demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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