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>

I've used xml-js - npm to get the desired result.

First of all I've installed xml-js via npm install xml-js

Then used the below code to get the output in json format

var convert = require('xml-js');
var xml = require('fs').readFileSync('./testscenario.xml', 'utf8');

var result = convert.xml2json(xml, {compact: true, spaces: 4});
console.log(result);