JSON to XML conversion in Node JS service (using xml2js)

Question

I need some help/advice with JSON to XML conversion in Node js. I have a service that gets a JSON object in request body that needs to convert to XML. I am able to achieve this using node-xml2js for json inputs with maximum one level of nested objects. But, it gets way more complicated with nested objects having attribute values. Attributes should be identified first, prefixed with $ sign and enclosed in curly braces before parsing through xml2js to get correct xml. Is there a better way of doing this where this complicated layer of reformatting the json input can be simplified? xml2js can converts this:

{
    "Level1":{  "$":{   "attribute":"value" },
                "Level2": {"$":{"attribute1":"05/29/2020",
                            "attribute2":"10","attribute3":"Pizza"}}
}

to this:(which is correct):

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Level1 attribute="value">
  <Level2 attribute1="05/29/2020" attribute2="10" attribute3="Pizza"/>
</Level1>

But actual json input is this:

{
    "Level1":{"attribute":"value",
              "Level2": {"attribute1":"05/29/2020",
                         "attribute2":"10","attribute3":"Pizza"} }
}

Expected same result:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Level1 attribute="value">
  <Level2 attribute1="05/29/2020" attribute2="10" attribute3="Pizza"/>
</Level1>

Please let me know if you have worked on similar requirements. Appreciate any help. Thank you.

Dave Ankin · Accepted Answer · 2022-06-05 18:04:19Z

4

This would be a way to change the object back to the format expected in the library, although it assumes that all non object keys are supposed to be attributes (is that a valid assumption for your application?)

function groupChildren(obj) {
  for(prop in obj) { // consider filtering for own properties (vs from prototype: for(prop of Object.keys(obj)) {
    if (typeof obj[prop] === 'object') {
      groupChildren(obj[prop]);
    } else {
      obj['$'] = obj['$'] || {};
      obj['$'][prop] = obj[prop];
      delete obj[prop];
    }
  }

  return obj;
}

and then used like so:

var xml2js = require('xml2js'); 
var obj = {
  Level1: {
    attribute: 'value',
    Level2: {
      attribute1: '05/29/2020',
      attribute2: '10',
      attribute3: 'Pizza'
    }
  }
};

var builder = new xml2js.Builder();
var xml = builder.buildObject(groupChildren(obj));

which prints out:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Level1 attribute="value">
  <Level2 attribute1="05/29/2020" attribute2="10" attribute3="Pizza"/>
</Level1>

edited Jun 5, 2022 at 18:04

answered May 29, 2020 at 5:02

Dave Ankin

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3 Comments

JavaNaresh Over a year ago

Thank you Dave. It works perfectly for me as there are only attributes in my scenario so I am accepting this as the correct answer. However, i'd like to try to enhance it for elements as well at some point. Thanks again.

Victor Over a year ago

Add this to the first line of the for-in loop if (!Object.prototype.hasOwnProperty.call(obj, prop)) continue;

Dave Ankin Over a year ago

@Vitim.us added caveat about properties from prototype

Elad Winkler · Accepted Answer · 2021-09-03 05:21:30Z

-1

you can use this library :nashwaan/xml-js

Like This:

  let xmlJ=require('xml-js');
  let parseToJson=(xml)=>{
        return new Promise(resolve => {
              let convert;
         
              convert=xmlJ.xml2json(xml,{compact:true});
              resolve(convert);
    
   });
 };

edited Sep 3, 2021 at 5:21

Elad Winkler

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answered May 29, 2020 at 5:50

Ashkan

419 bronze badges

1 Comment

mLamaa Over a year ago

user is requesting JSON to XML not XML to JSON

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