Add xml2json function

[mtuchi]

Short Summary

Add xml2json function for easy conversion of xml string to json

Why ?

We need to traverse the XML response from a SOAP based API into a json object so that we can easily map and transform the data

Why not use parseXML?

Well we have tried using parseXML to traverse the XML response but it's not easy to map the XML response, You have to go through the cheerio documentation and figure out how to traverse the xml response

See example here 👇🏽

fn((state) => {
  return {
    ...state,
    data: {
      body: "<xml><<response>cheeseburger</response></xml>",
    },
  };
});

// Extract and parse the data from the response payload
parseXML(dataValue("body"), ($) => {
  const response = $("response");
  const $inner = $.load(response.text());

  const payload = [];
  $inner("payload ledger line").each((i, elm) => {
    payload.push({
      res: $(this).find("menu").text,
    });
  });
  console.log(payload)
});

The approach above might work but it's difficult to troubleshoot, there is no documentation for it on our adaptors and not easy getting proper mapping that you can confidently trust not to break

Side Note

Currently cheerio [The library we are using behind parseXML] has a method called $.exctract which seems to provide a simple interface for extracting data from HTML document. The down side is although this function is documented, it not release yet [See GitHub issue here]. A library that was born out of that GitHub issue - https://github.com/denkan/cheerio-json-mapper which might be useful for adding $.exctract ability in parseXML

Implementation Note

Add xml2json function with the following signature

See options list here - https://github.com/Leonidas-from-XIV/node-xml2js?search=1#options
interface Xml2JsonOptions {
  [key: string]: any;
}
xml2json(xmlString: string, options: Xml2JsonOptions, callback: (state: any) => any))

[mtuchi]

Not needed for now