xml2ts

xml2ts
===========

This is a remixed version of the original work of Marek Kubica's node-xml2js.

####Differences between this and the original version
* Complete rewrite in typescript.
* Some features removed because of the increased strictness of being type safe.
* Some features or behaviours altered.
* Introduced XmlTsNode as resulting object.
* Typed configuration object
* Typed validators and processors
* Position tracking. You always know the actual node position within the original xml.
* Tests are rewrote to a more standard Mocha and Chai.

Documentation and the builder side is still in progress. The parsing side is done

Description
===========

Simple XML to JavaScript object converter.
Uses sax-js and
xmlbuilder-js.

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

This version is somewhat rewrote to typescript. Introduced XmlTsNode as the resulting object.
Position of each node are

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 is
what you're looking for!

Installation
============

Simplest way to install xml2ts is to use npm, just npm
install xml2ts which will download xml2js and all dependencies.

Usage
=====

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

Shoot-and-forget usage
----------------------

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

``typescript
import {parseString} from 'xml2ts';
var xml = "Hello xml2js!"
const result = await parseString(xml);
`

If you need some special options, fear not, xml2ts supports a number of
options (see below), you can specify these as second argument:

`typescript
import {parseString} from 'xml2ts';
parseString(xml, {trim: true});
`

Simple as pie usage
-------------------

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

`typescript
import * as fs = from 'fs';
import {Parser, parserDefaults, XmlTsNode} from 'xml2ts';

async function f(xml: string): Promise {
const parser = new Parser(parserDefaults);
return await parser.parseString(xml);
}
`

Parsing multiple files
----------------------

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

* You can create one xml2js.Parser per file. That's the recommended one
and is promised to always just work.

So you wanna some JSON?
-----------------------

Just wrap the result object in a call to JSON.stringify like this
JSON.stringify(result). You get a string containing the JSON representation
of the parsed object that you can feed to JSON-hungry consumers.

$3

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

Example declaring a default namespace on the root element:

`javascript
let obj = {
Foo: {
$: {
"xmlns": "http://foo.com"
}
}
};
`
Result of buildObject(obj):
`xml

`
Example declaring non-default namespaces on non-root elements:
`javascript
let obj = {
'foo:Foo': {
$: {
'xmlns:foo': 'http://foo.com'
},
'bar:Bar': {
$: {
'xmlns:bar': 'http://bar.com'
}
}
}
}
`
Result of buildObject(obj):
`xml



`


Processing attribute, tag names and values
------------------------------------------

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):

`javascript

function nameToUpperCase(name){
return name.toUpperCase();
}

//transform all attribute and tag names and values to uppercase
parseString(xml, {
tagNameProcessors: [nameToUpperCase],
attrNameProcessors: [nameToUpperCase],
valueProcessors: [nameToUpperCase],
attrValueProcessors: [nameToUpperCase]},
function (err, result) {
// processed data
});
`

The tagNameProcessors and attrNameProcessors options
accept an Array of functions with the following signature:

`javascript
function (name){
//do something with name
return name
}
`

The attrValueProcessors and valueProcessors options
accept an Array of functions with the following signature:

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

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

- normalize: transforms the name to lowercase.
(Automatically used when options.normalize is set to true)

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

- stripPrefix: strips the xml namespace prefix. E.g will become 'Bar'.
(N.B.: the xmlns prefix is NOT stripped.)

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

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

Options
=======

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

* attrkey (default: $): Prefix that is used to access the attributes.
Version 0.1 default was @.
* charkey (default: _): Prefix that is used to access the character
content. Version 0.1 default was #.
* explicitCharkey (default: false)
* trim (default: false): Trim the whitespace at the beginning and end of
text nodes.
* normalizeTags (default: false): Normalize all tag names to lowercase.
* normalize (default: false): Trim whitespaces inside text nodes.
* explicitRoot (default: true): Set this if you want to get the root
node in the resulting object.
* emptyTag (default: ''): what will the value of empty nodes be.
* explicitArray (default: true): Always put child nodes in an array if
true; otherwise an array is created only if there is more than one.
* ignoreAttrs (default: false): Ignore all XML attributes and only create
text nodes.
* mergeAttrs (default: false): Merge attributes and child elements as
properties of the parent, instead of keying attributes off a child
attribute object. This option is ignored if ignoreAttrs is true.
* validator (default null): You can specify a callable that validates
the resulting structure somehow, however you want. See unit tests
for an example.
* xmlns (default false): Give each element a field usually called '$ns'
(the first character is the same as attrkey) that contains its local name
and namespace URI.
* explicitChildren (default false): Put child elements to separate
property. Doesn't work with mergeAttrs = true. If element has no children
then "children" won't be created. Added in 0.2.5.
* childkey (default $$): Prefix that is used to access child elements if
explicitChildren is set to true. Added in 0.2.5.
* preserveChildrenOrder (default false): Modifies the behavior of
explicitChildren so that the value of the "children" property becomes an
ordered array. When this is true, every node will also get a #name field
whose value will correspond to the XML nodeName, so that you may iterate
the "children" array and still be able to determine node names. The named
(and potentially unordered) properties are also retained in this
configuration at the same level as the ordered "children" array. Added in
0.4.9.
* charsAsChildren (default false): Determines whether chars should be
considered children if explicitChildren is on. Added in 0.2.5.
* includeWhiteChars (default false): Determines whether whitespace-only
text nodes should be included. Added in 0.4.17.
async (default false): Should the callbacks be async? This might* be
an incompatible change if your code depends on sync execution of callbacks.
Future versions of xml2js might change this default, so the recommendation
is to not depend on sync execution anyway. Added in 0.2.6.
* strict (default true): Set sax-js to strict or non-strict parsing mode.
Defaults to true which is highly recommended, since parsing HTML which
is not well-formed XML might yield just about anything. Added in 0.2.7.
* attrNameProcessors (default: null): Allows the addition of attribute
name processing functions. Accepts an Array of functions with following
signature:
`javascript
function (name){
//do something with name
return name
}
`
Added in 0.4.14
* attrValueProcessors (default: null): Allows the addition of attribute
value processing functions. Accepts an Array of functions with following
signature:
`javascript
function (name){
//do something with name
return name
}
`
Added in 0.4.1
* tagNameProcessors (default: null): Allows the addition of tag name
processing functions. Accepts an Array of functions with following
signature:
`javascript
function (name){
//do something with name
return name
}
`
Added in 0.4.1
* valueProcessors (default: null): Allows the addition of element value
processing functions. Accepts an Array of functions with following
signature:
`javascript
function (name){
//do something with name
return name
}
`
Added in 0.4.6

Running tests, development
==========================

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 using npm test directly
from the project root. This runs zap to discover all the tests and execute
them.

If you like to contribute, keep in mind that xml2ts is written in
Typescript, so don't develop on the JavaScript files that are checked into
the repository for convenience reasons. Also, please write some unit test to
check your behaviour and if it is some user-facing thing, add some
documentation to this README, so people will know it exists. Thanks in advance!

Getting support
===============

Please, if you have a problem with the library, first make sure you read this
README. If you read this far, thanks, you're good. Then, please make sure your
problem really is with xml2ts. It is? Okay, then I'll look at it. Send me a
mail and we can talk. Please don't open issues, as I don't think that is the
proper forum for support problems. Some problems might as well really be bugs
in xml2ts`, 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.