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.
List of some applications/projects using Fast XML Parser. (Raise an issue to submit yours)
- 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.
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 a CDN
var jsonObj = parser.parse(xmlData [,options] );
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 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
$xml2js [-ns|-a|-c|-v|-V] <filename> [-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
var result = parser.validate(xmlData);
if (result !== true) console.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.
- 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 totrue
- 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.
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.
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 |
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.
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