'preserveChildrenOrder' option not working

[Kandy16]

The input xml is as shown
<data>
<a>A</a>
<a>A</a>
<b>B</b>
<b>B</b>
<c>C</c>
<c>C</c>
<a>A</a>
<b>B</b>
<c>C</c>
</data>

and the output is
{ data:
{ a: [ 'A', 'A', 'A' ],
b: [ 'B', 'B', 'B' ],
c: [ 'C', 'C', 'C' ] } }

I saw that it will be available from 0.4.9 version. But the latest version available is 0.4.8. But I downloaded the code and tried the above input.

This feature is very important for me. Please let me know when this will be released

Thanks In Advance

[Leonidas-from-XIV]

You can just use the git version in the meantime and let me know if it works, which would help me to make sure I'm realeasing a 0.4.9 that actually works properly.

[slippyex]

Hi there,

Unfortunately it does not work with the current git version for my use case.
I have a somewhat similar problem as Kandy16 has.

Here's an example where you can reproduce the behavior.

var fs = require('fs'),
    xml2js = require('./xml2js');
var parser = new xml2js.Parser(
{
        preserveChildrenOrder: true,
        explicitArray: false,
        explicitChildren: true, 
        charkey: "content",
        attrkey: "props",
        childkey: "content",
        emptyTag: {}
    } 
);
parser.addListener('end', function(result) {
    console.dir(JSON.stringify(result));
});
fs.readFile(__dirname + '/tmp.xml', function(err, data) {
    parser.parseString(data);
});

The corresponding "tmp.xml" file is like

<A>
  <B>B1</B>
  <C>C1</C>
  <B>B2</B>
</A>

When I now set both, "explicitChildren" AND "preserveChildrenOrder" to true, it fails with this error message:

events.js:85
      throw er; // Unhandled 'error' event
            ^
TypeError: undefined is not a function
    at Object.onclosetag (/Users/me/workspaces/xml2js-git/xml2js.js:403:41)
    at emit (/Users/me/workspaces/xml2js-git/node_modules/sax/lib/sax.js:615:33)
    at emitNode (/Users/me/workspaces/xml2js-git/node_modules/sax/lib/sax.js:620:3)
    at closeTag (/Users/me/workspaces/xml2js-git/node_modules/sax/lib/sax.js:861:5)
    at Object.write (/Users/me/workspaces/xml2js-git/node_modules/sax/lib/sax.js:1294:29)
    at Parser.exports.Parser.Parser.parseString (/Users/me/workspaces/xml2js-git/xml2js.js:478:31)
    at Parser.parseString (/Users/me/workspaces/xml2js-git/xml2js.js:6:59)
    at /Users/me/workspaces/xml2js-git/test.js:20:12
    at fs.js:336:14
    at FSReqWrap.oncomplete (fs.js:99:15)

Thanks in advance.

[ds82]

I'm working on a fix for this. Would like to hear your opinions.
ds82/node-xml2js@4179b44

I think the only reliable solution for this is to introduce an explicit index when converting xml to js(on) (at least when you use explicitChildren=false). The index will be removed when json is converted back to xml, but it will dictate the order of the xml tags.

In my project this would look like this:

<parent>
  <a>1</a>
  <b>2</b>
  <a>3</a>
</parent>

the json looks something like this (actually skipped some details to improve readability):

{
  parent: {
    a: [{
      _$: 1,
      #index: 0
    }, {
      _$: 3,
      #index: 2
    }],
    b: {
      _$: 2,
      #index: 1
    }
  }
}

Without my patch, the only way to produce this JSON would be to have an actual #index XML tag, however since a XML tag can only start with an underscore or a letter, I see no conflicts here.

[ashelley]

@ds82 Thank you +1

Just used your fork to process some SVG that was breaking without your patches.

[gvillo]

any fix for this? #index prop would be very useful for me!

[ogomez92]

Still waiting for a fix :(

[eMahtab]

I switched to https://github.com/nashwaan/xml-js that worked for my requirements. It preserves the order.

Also if your input xml is deeply nested, you might find the https://marketplace.visualstudio.com/items?itemName=nidu.copy-json-path plugin useful (I guess similar plugins are available for other IDE's as well). You can easily navigate the output JSON using this plugin. This saved a lot of time for me.