# [fast-xml-parser](https://www.npmjs.com/package/fast-xml-parser)
Validate XML, Parse XML to JS/JSON and vise versa, or parse XML to Nimn rapidly without C/C++ based libraries and no callback
[](#backers) [](#sponsors) [](https://snyk.io/test/github/naturalintelligence/fast-xml-parser)
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](https://naturalintelligence.github.io/fast-xml-parser/)
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### Main Features
* Validate XML data syntactically
* Transform XML to JSON or Nimn
* Transform JSON back to XML
* Works with node packages, in browser, and in CLI (press try me button above for demo)
* Faster than any pure JS implementation.
* It can handle big files (tested up to 100mb).
* Various options are available to customize the transformation
* You can parse CDATA as separate property.
* You can prefix attributes or group them to separate property. Or can ignore them from result completely.
* You can parse tag's or attribute's value to premitive type: string, integer, float, or boolean. And can optionally decode for HTML char.
* You can remove namespace from tag or attribute name while parsing
* It supports boolean attributes, if configured.
## How to use
To use it in **NPM package** install it first
`$npm install fast-xml-parser` or using [yarn](https://yarnpkg.com/) `$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](https://github.com/NaturalIntelligence/fast-xml-parser/blob/master/lib/parser.js) Or directly from [CDN](https://cdnjs.com/libraries/fast-xml-parser)
### XML to JSON or XML to Nimn
```js
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,
decodeHTMLchar: false,
cdataTagName: "__cdata", //default is 'false'
cdataPositionChar: "\\c",
};
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);
```
* NIMN (निम्न) data is the schema aware compressed form of data. It reduces JSON up to 50% or more of original data by removing field information. Check [specification](https://github.com/nimndata/spec) for more detail.
* Check [nimnjs](https://github.com/nimndata/nimnjs-node) to know more about schema, json to nimndata and reverse transformation.
**OPTIONS** :
* **attributeNamePrefix** : prepend given string to attribute name for identification
* **attrNodeName**: (Valid name) Group all the attributes as properties of given name.
* **ignoreAttributes** : Ignore attributes to be parsed.
* **ignoreNameSpace** : Remove namespace string from tag and attribute names.
* **allowBooleanAttributes** : a tag can have attributes without any value
* **parseNodeValue** : Parse the value of text node to float, integer, or boolean.
* **parseAttributeValue** : Parse the value of an attribute to float, integer, or boolean.
* **trimValues** : trim string values of an attribute or node
* **decodeHTMLchar** : decodes any named and numerical character HTML references excluding CDATA part.
* **cdataTagName** : If specified, parser parse CDATA as nested tag instead of adding it's value to parent tag.
* **cdataPositionChar** : It'll help to covert JSON back to XML without loosing CDATA position.
To use from command line
```bash
$xml2js [-ns|-a|-c|-v|-V] [-o outputfile.json]
$cat xmlfile.xml | xml2js [-ns|-a|-c|-v|-V] [-o outputfile.json]
```
* -ns : To include namespaces (bedefault ignored)
* -a : To ignore attributes
* -c : To ignore value conversion (i.e. "-3" will not be converted to number -3)
* -v : validate before parsing
* -V : only validate
To use it **on webpage**
```js
var result = parser.validate(xmlData);
if(result !== true) cnosole.log(result.err);
var jsonObj = parser.parse(xmlData);
```
### JSON / JS Object to XML
```js
var Parser = require("fast-xml-parser").j2xParser;
//default options need not to set
var defaultOptions = {
attributeNamePrefix : "@_",
attrNodeName: "@", //default is false
textNodeName : "#text",
ignoreAttributes : true,
encodeHTMLchar: false,
cdataTagName: "__cdata", //default is false
cdataPositionChar: "\\c",
format: false,
indentBy: " ",
supressEmptyNode: false
};
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.
* **attributeNamePrefix** : Identify attributes with this prefix otherwise treat them as a tag.
* **attrNodeName**: Identify attributes when they are grouped under single property.
* **ignoreAttributes** : Don't check for attributes. Treats everything as tag.
* **encodeHTMLchar** : encodes values (except cdata values) when writing to XML.
* **cdataTagName** : If specified, parse matching tag as CDATA
* **cdataPositionChar** : Identify the position where CDATA tag should be placed. If it is blank then CDATA will be added in the last of tag's value.
* **format** : If set to true, then format the XML output.
* **indentBy** : indent by this char `when` format is set to `true`
* **supressEmptyNode** : If set to `true`, tags with no value (text or nested tags) are written as self closing tags.
## Comparision
We've copared 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 liraries 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.
### Benchmark report
| 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 |
* -1 indicates error or incorrect output.
#### Benchmark for JSON to XML
| 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|
### Worth to mention
- **[NIMN निम्न](https://github.com/nimndata/spec)** : Schema aware object compression
- **[imglab](https://github.com/NaturalIntelligence/imglab)** : Web based tool to label images for object. So that they can be used to train dlib or other object detectors. You can integrate 3rd party libraries for fast labeling.
- [fast-lorem-ipsum](https://github.com/amitguptagwl/fast-lorem-ipsum) : Generate lorem ipsum words, sentences, paragraph very quickly.
- [stubmatic](https://github.com/NaturalIntelligence/Stubmatic) : A stub server to mock behaviour of HTTP(s) / REST / SOAP services.
- [fastify-xml-body-parser](https://github.com/NaturalIntelligence/fastify-xml-body-parser/) : Fastify plugin / module to parse XML payload / body into JS object using fast-xml-parser.
- [Grapes](https://github.com/amitguptagwl/grapes) : Flexible Regular expression engine (for java) which can be applied on char stream. (under development)
## Contributors
This project exists thanks to [all](graphs/contributors) the people who contribute. [[Contribute](CONTRIBUTING.md)].
### Lead Maintainers
[](https://github.com/Delagen)
### Collaborators
[](https://github.com/Tatsh)
[](https://github.com/alfonsomunozpomer)
[](https://github.com/monkeywithacupcake)
[](https://github.com/EyesOnlyNet)
[](https://github.com/abbyarmada)
[](https://github.com/j0k3r)
[](https://github.com/HaroldPutman)
## Backers
Thank you to all our backers! 🙏 [[Become a backer](https://opencollective.com/fast-xml-parser#backer)]
## Sponsors
Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [[Become a sponsor](https://opencollective.com/fast-xml-parser#sponsor)]
