# [fast-xml-parser](https://www.npmjs.com/package/fast-xml-parser)
Validate XML, Parse XML to JS/JSON and vice versa, or parse XML to Nimn rapidly without C/C++ based libraries and no callback
> This project welcomes **contributors**. If you have a feature you'd like to see implemented or a bug you'd liked fixed, the best and fastest way to make that happen is to implement it and submit a PR. Basic knowledge of JS is sufficient. Feel free to ask for any guidance.
## Users
List of some applications/projects using Fast XML Parser. (Raise an issue to submit yours)
### Join this project as collaborator / maintainer.
[](#backers) [](#sponsors) [](https://snyk.io/test/github/naturalintelligence/fast-xml-parser)
[![NPM quality][quality-image]][quality-url]
[](https://travis-ci.org/NaturalIntelligence/fast-xml-parser)
[](https://coveralls.io/github/NaturalIntelligence/fast-xml-parser?branch=master)
[
](https://naturalintelligence.github.io/fast-xml-parser/)
[](https://npm.im/fast-xml-parser)
[quality-image]: http://npm.packagequality.com/shield/fast-xml-parser.svg?style=flat-square
[quality-url]: http://packagequality.com/#?package=fast-xml-parser
### 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 primitive type: string, integer, float, hexadecimal, 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 a [CDN](https://cdnjs.com/libraries/fast-xml-parser)
### XML to JSON
```js
var jsonObj = parser.parse(xmlData [,options] );
```
```js
var parser = require('fast-xml-parser');
var he = require('he');
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",
localeRange: "", //To support non english character in tag/attribute values.
parseTrueNumberOnly: false,
attrValueProcessor: a => he.decode(a, {isAttributeValue: true}),//default is a=>a
tagValueProcessor : a => he.decode(a) //default is a=>a
};
if( parser.validate(xmlData) === true) { //optional (it'll return an object in case it's not valid)
var jsonObj = parser.parse(xmlData,options);
}
// Intermediate obj
var tObj = parser.getTraversalObj(xmlData,options);
var jsonObj = parser.convertToJson(tObj,options);
```
#### Note: [he](https://www.npmjs.com/package/he) library is used in this example
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** : This options has been removed from 3.3.4. Instead, use tagValueProcessor, and attrValueProcessor. See above example.
* **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 losing CDATA position.
* **localeRange**: Parser will accept non-English character in tag or attribute name. Check #87 for more detail. Eg `localeRange: "a-zA-Zа-яёА-ЯЁ"`
* **parseTrueNumberOnly**: if true then values like "+123", or "0123" will not be parsed as number.
* **tagValueProcessor** : Process tag value during transformation. Like HTML decoding, word capitalization, etc. Applicable in case of string only.
* **attrValueProcessor** : Process attribute value during transformation. Like HTML decoding, word capitalization, etc. Applicable in case of string only.
* **stopNodes** : an array of tag names which are not required to be parsed. Instead their values are parsed as string.
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 (by default 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) console.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,
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.
* **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** : This option has been removed from 3.3.4. Use tagValueProcessor, and attrValueProcessor instead. See above example.
* **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.
* **tagValueProcessor** : Process tag value during transformation. Like HTML encoding, word capitalization, etc. Applicable in case of string only.
* **attrValueProcessor** : Process attribute value during transformation. Like HTML encoding, word capitalization, etc. Applicable in case of string only.
## Benchmark
#### XML to JSON
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.
#### JSON to XML
report
| 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|
### Limitations
Currently FXP fails to parse XML with attributes has ">" in the value. This problem is left open as change in regex for its fix is degrading the performance. And the parser become very slow in case of long attrbute names.
### Worth to mention
- **[BigBit standard)](https://github.com/amitguptagwl/bigbit)** : A standard to reprent any number in the universe in comparitively less space and without precision loss. A standard to save space to represent any text string in comparision of UTF encoding.
- **[imglab](https://github.com/NaturalIntelligence/imglab)** : Speedup and simplify image labeling / annotation. Supports multiple formats, one click annotation, easy interface and much more. There are more than 20k images are annotated every month.
- **[अनुमार्गक (anumargak)](https://github.com/NaturalIntelligence/anumargak)** : The fastest and simple router for node js web frameworks with many unique features.
- [stubmatic](https://github.com/NaturalIntelligence/Stubmatic) : A stub server to mock behaviour of HTTP(s) / REST / SOAP services, incuding DynamoDB calls. You can also mock binary formats.
- [मुनीम (Muneem)](https://github.com/muneem4node/muneem) : A webframework made for all team members. Faster tha fastify, express, koa, hapi and others.
- [शब्दावली (shabdawali)](https://github.com/amitguptagwl/shabdawali) : Amazing human like typing effects beyond your imagination.
## Contributors
This project exists thanks to [all](graphs/contributors) the people who contribute. [[Contribute](CONTRIBUTING.md)].
## 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)]
