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Ever had the urge to parse XML? And wanted to access the data in some sane,easy way? Don't want to compile a C parser, for whatever reason? Then xml2js iswhat you're looking for!

Simple XML to JavaScript object converter. It supports bi-directional conversion.Usessax-js andxmlbuilder-js.

Note: If you're looking for a full DOM parser, you probably wantJSDom.

Simplest way to installxml2js is to usenpm, justnpm install xml2js which will download xml2js and all dependencies.

xml2js is also available viaBower, justbower install xml2js which will download xml2js and all dependencies.

No extensive tutorials required because you are a smart developer! The task ofparsing XML should be an easy one, so let's make it so! Here's some examples.

You want to parse XML as simple and easy as possible? It's dangerous to goalone, take this:

varparseString=require('xml2js').parseString;varxml="<root>Hello xml2js!</root>"parseString(xml,function(err,result){console.dir(result);});

Can't get easier than this, right? This works starting withxml2js 0.2.3.With CoffeeScript it looks like this:

{parseString}=require'xml2js'xml="<root>Hello xml2js!</root>"parseString xml, (err,result)->console.dir result

If you need some special options, fear not,xml2js supports a number ofoptions (see below), you can specify these as second argument:

parseString(xml,{trim:true},function(err,result){});

That's right, if you have been using xml-simple or a home-grownwrapper, this was added in 0.1.11 just for you:

varfs=require('fs'),xml2js=require('xml2js');varparser=newxml2js.Parser();fs.readFile(__dirname+'/foo.xml',function(err,data){parser.parseString(data,function(err,result){console.dir(result);console.log('Done');});});

Look ma, no event listeners!

You can also usexml2js fromCoffeeScript, further reducingthe clutter:

fs=require'fs',xml2js=require'xml2js'parser=newxml2js.Parser()fs.readFile__dirname+'/foo.xml', (err,data)->parser.parseString data, (err,result)->console.dir resultconsole.log'Done.'

But what happens if you forget thenew keyword to create a newParser? Inthe middle of a nightly coding session, it might get lost, after all. Worrynot, we got you covered! Starting with 0.2.8 you can also leave it out, inwhich casexml2js will helpfully add it for you, no bad surprises andinexplicable bugs!

varxml2js=require('xml2js');varxml='<foo></foo>';// With parservarparser=newxml2js.Parser(/* options */);parser.parseStringPromise(xml).then(function(result){console.dir(result);console.log('Done');}).catch(function(err){// Failed});// Without parserxml2js.parseStringPromise(xml/*, options */).then(function(result){console.dir(result);console.log('Done');}).catch(function(err){// Failed});

If you want to parse multiple files, you have multiple possibilities:

• You can create onexml2js.Parser per file. That's the recommended oneand is promised to alwaysjust work.
• You can callreset() on your parser object.
• You can hope everything goes well anyway. This behaviour is notguaranteed work always, if ever. Use option #1 if possible. Thanks!

Just wrap theresult object in a call toJSON.stringify like thisJSON.stringify(result). You get a string containing the JSON representationof the parsed object that you can feed to JSON-hungry consumers.

You might wonder why, usingconsole.dir orconsole.log the output at somelevel is only[Object]. Don't worry, this is not becausexml2js got lazy.That's because Node usesutil.inspect to convert the object into strings andthat function stops afterdepth=2 which is a bit low for most XML.

To display the whole deal, you can useconsole.log(util.inspect(result, false, null)), which displays the whole result.

So much for that, but what if you useeyes for nice colored output and ittruncates the output with…? Don't fear, there's also a solution for that,you just need to increase themaxLength limit by creating a custom inspectorvar inspect = require('eyes').inspector({maxLength: false}) and then you caneasilyinspect(result).

Since 0.4.0, objects can be also be used to build XML:

varxml2js=require('xml2js');varobj={name:"Super",Surname:"Man",age:23};varbuilder=newxml2js.Builder();varxml=builder.buildObject(obj);

will result in:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><root>  <name>Super</name>  <Surname>Man</Surname>  <age>23</age></root>

At the moment, a one to one bi-directional conversion is guaranteed only fordefault configuration, except forattrkey,charkey andexplicitArray optionsyou can redefine to your taste. Writing CDATA is supported via setting thecdataoption totrue.

To specify attributes:

varxml2js=require('xml2js');varobj={root:{$:{id:"my id"},_:"my inner text"}};varbuilder=newxml2js.Builder();varxml=builder.buildObject(obj);

will result in:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><rootid="my id">my inner text</root>

You can generate XML that declares XML namespace prefix / URI pairs with xmlns attributes.

Example declaring a default namespace on the root element:

letobj={Foo:{$:{"xmlns":"http://foo.com"}}};

Result ofbuildObject(obj):

<Fooxmlns="http://foo.com"/>

Example declaring non-default namespaces on non-root elements:

letobj={'foo:Foo':{$:{'xmlns:foo':'http://foo.com'},'bar:Bar':{$:{'xmlns:bar':'http://bar.com'}}}}

Result ofbuildObject(obj):

<foo:Fooxmlns:foo="http://foo.com">  <bar:Barxmlns:bar="http://bar.com"/></foo:Foo>

Since 0.4.1 you can optionally provide the parser with attribute name and tag name processors as well as element value processors (Since 0.4.14, you can also optionally provide the parser with attribute value processors):

functionnameToUpperCase(name){returnname.toUpperCase();}//transform all attribute and tag names and values to uppercaseparseString(xml,{tagNameProcessors:[nameToUpperCase],attrNameProcessors:[nameToUpperCase],valueProcessors:[nameToUpperCase],attrValueProcessors:[nameToUpperCase]},function(err,result){// processed data});

ThetagNameProcessors andattrNameProcessors optionsaccept anArray of functions with the following signature:

function(name){//do something with `name`returnname}

TheattrValueProcessors andvalueProcessors optionsaccept anArray of functions with the following signature:

function(value,name){//`name` will be the node name or attribute name//do something with `value`, (optionally) dependent on the node/attr namereturnvalue}

Some processors are provided out-of-the-box and can be found inlib/processors.js:

• normalize: transforms the name to lowercase.(Automatically used whenoptions.normalize is set totrue)

• firstCharLowerCase: transforms the first character to lower case.E.g. 'MyTagName' becomes 'myTagName'

• stripPrefix: strips the xml namespace prefix. E.g<foo:Bar/> will become 'Bar'.(N.B.: thexmlns prefix is NOT stripped.)

• parseNumbers: parses integer-like strings as integers and float-like strings as floatsE.g. "0" becomes 0 and "15.56" becomes 15.56

• parseBooleans: parses boolean-like strings to booleansE.g. "true" becomes true and "False" becomes false

Apart from the default settings, there are a number of options that can bespecified for the parser. Options are specified bynew Parser({optionName: value}). Possible options are:

• attrkey (default:$): Prefix that is used to access the attributes.Version 0.1 default was@.
• charkey (default:_): Prefix that is used to access the charactercontent. Version 0.1 default was#.
• explicitCharkey (default:false) Determines whether or not to useacharkey prefix for elements with no attributes.
• trim (default:false): Trim the whitespace at the beginning and end oftext nodes.
• normalizeTags (default:false): Normalize all tag names to lowercase.
• normalize (default:false): Trim whitespaces inside text nodes.
• explicitRoot (default:true): Set this if you want to get the rootnode in the resulting object.
• emptyTag (default:''): what will the value of empty nodes be. In caseyou want to use an empty object as a default value, it is better to provide a factoryfunction() => ({}) instead. Without this function a plain object wouldbecome a shared reference across all occurrences with unwanted behavior.
• explicitArray (default:true): Always put child nodes in an array iftrue; otherwise an array is created only if there is more than one.
• ignoreAttrs (default:false): Ignore all XML attributes and only createtext nodes.
• mergeAttrs (default:false): Merge attributes and child elements asproperties of the parent, instead of keying attributes off a childattribute object. This option is ignored ifignoreAttrs istrue.
• validator (defaultnull): You can specify a callable that validatesthe resulting structure somehow, however you want. See unit testsfor an example.
• xmlns (defaultfalse): Give each element a field usually called '$ns'(the first character is the same as attrkey) that contains its local nameand namespace URI.
• explicitChildren (defaultfalse): Put child elements to separateproperty. Doesn't work withmergeAttrs = true. If element has no childrenthen "children" won't be created. Added in 0.2.5.
• childkey (default$$): Prefix that is used to access child elements ifexplicitChildren is set totrue. Added in 0.2.5.
• preserveChildrenOrder (defaultfalse): Modifies the behavior ofexplicitChildren so that the value of the "children" property becomes anordered array. When this istrue, every node will also get a#name fieldwhose value will correspond to the XML nodeName, so that you may iteratethe "children" array and still be able to determine node names. The named(and potentially unordered) properties are also retained in thisconfiguration at the same level as the ordered "children" array. Added in0.4.9.
• charsAsChildren (defaultfalse): Determines whether chars should beconsidered children ifexplicitChildren is on. Added in 0.2.5.
• includeWhiteChars (defaultfalse): Determines whether whitespace-onlytext nodes should be included. Added in 0.4.17.
• async (defaultfalse): Should the callbacks be async? Thismight bean incompatible change if your code depends on sync execution of callbacks.Future versions ofxml2js might change this default, so the recommendationis to not depend on sync execution anyway. Added in 0.2.6.
• strict (defaulttrue): Set sax-js to strict or non-strict parsing mode.Defaults totrue which ishighly recommended, since parsing HTML whichis not well-formed XML might yield just about anything. Added in 0.2.7.
• attrNameProcessors (default:null): Allows the addition of attributename processing functions. Accepts anArray of functions with followingsignature:

  function(name){//do something with `name`returnname}

  Added in 0.4.14
• attrValueProcessors (default:null): Allows the addition of attributevalue processing functions. Accepts anArray of functions with followingsignature:

  function(value,name){//do something with `name`returnname}

  Added in 0.4.1
• tagNameProcessors (default:null): Allows the addition of tag nameprocessing functions. Accepts anArray of functions with followingsignature:

  function(name){//do something with `name`returnname}

  Added in 0.4.1
• valueProcessors (default:null): Allows the addition of element valueprocessing functions. Accepts anArray of functions with followingsignature:

  function(value,name){//do something with `name`returnname}

  Added in 0.4.6

These options are specified bynew Builder({optionName: value}).Possible options are:

• attrkey (default:$): Prefix that is used to access the attributes.Version 0.1 default was@.
• charkey (default:_): Prefix that is used to access the charactercontent. Version 0.1 default was#.
• rootName (defaultroot or the root key name): root element name to be used in caseexplicitRoot isfalse or to override the root element name.
• renderOpts (default{ 'pretty': true, 'indent': ' ', 'newline': '\n' }):Rendering options for xmlbuilder-js.
  • pretty: prettify generated XML
  • indent: whitespace for indentation (only when pretty)
  • newline: newline char (only when pretty)
• xmldec (default{ 'version': '1.0', 'encoding': 'UTF-8', 'standalone': true }:XML declaration attributes.
  • xmldec.version A version number string, e.g. 1.0
  • xmldec.encoding Encoding declaration, e.g. UTF-8
  • xmldec.standalone standalone document declaration: true or false
• doctype (defaultnull): optional DTD. Eg.{'ext': 'hello.dtd'}
• headless (default:false): omit the XML header. Added in 0.4.3.
• allowSurrogateChars (default:false): allows using characters from the Unicodesurrogate blocks.
• cdata (default:false): wrap text nodes in<![CDATA[ ... ]]> instead ofescaping when necessary. Does not add<![CDATA[ ... ]]> if it is not required.Added in 0.4.5.

renderOpts,xmldec,doctype andheadless pass through toxmlbuilder-js.

Version 0.2 changed the default parsing settings, but version 0.1.14 introducedthe default settings for version 0.2, so these settings can be tried before themigration.

varxml2js=require('xml2js');varparser=newxml2js.Parser(xml2js.defaults["0.2"]);

To get the 0.1 defaults in version 0.2 you can just usexml2js.defaults["0.1"] in the same place. This provides you with enough timeto migrate to the saner way of parsing inxml2js 0.2. We try to make themigration as simple and gentle as possible, but some breakage cannot beavoided.

So, what exactly did change and why? In 0.2 we changed some defaults to parsethe XML in a more universal and sane way. So we disablednormalize andtrimsoxml2js does not cut out any text content. You can reenable this at will ofcourse. A more important change is that we return the root tag in the resultingJavaScript structure via theexplicitRoot setting, so you need to access thefirst element. This is useful for anybody who wants to know what the root nodeis and preserves more information. The last major change was to enableexplicitArray, so everytime it is possible that one might embed more than onesub-tag into a tag, xml2js >= 0.2 returns an array even if the array justincludes one element. This is useful when dealing with APIs that returnvariable amounts of subtags.

The development requirements are handled by npm, you just need to install them.We also have a number of unit tests, they can be run usingnpm test directlyfrom the project root. This runs zap to discover all the tests and executethem.

If you like to contribute, keep in mind thatxml2js is written inCoffeeScript, so don't develop on the JavaScript files that are checked intothe repository for convenience reasons. Also, please write some unit test tocheck your behaviour and if it is some user-facing thing, add somedocumentation to this README, so people will know it exists. Thanks in advance!

Please, if you have a problem with the library, first make sure you read thisREADME. If you read this far, thanks, you're good. Then, please make sure yourproblem really is withxml2js. It is? Okay, then I'll look at it. Send me amail and we can talk. Please don't open issues, as I don't think that is theproper forum for support problems. Some problems might as well really be bugsinxml2js, if so I'll let you know to open an issue instead :)

But if you know you really found a bug, feel free to open an issue instead.