Converting JSON to CSV on the fly

//########################################################################################
// Thejesh GN https://thejeshgn.com
//
// This converts the JSON into CSV so it can be used by DataWrapper
// This is a hack where I combined piecies of code from various projects
// I have added link to those below if you want to check them out
//
// I love JSON to CSV converter by Eric Mill, https://konklone.io/json/ 
// Source code of it is at https://github.com/konklone/json
// It does an awesome job of converting JSON to CSV in the front end
//
// I wanted to do the same in backend and the pipedream seemed like a good place
// To host that serverless code. at some point I will write a proper serverless code
// Where if I send the url of JSON it will return CSV. Until then this hack is good 
// enough for me.
//
// The final datawrapper graph is at https://datawrapper.dwcdn.net/ThC0E/2/
// It caches the data, so its not a major hit on pipedream.
//########################################################################################
const axios = require('axios')

//########################################################################################
// Pass in the objects to merge as arguments.
// For a deep extend, set the first argument to `true`.
// https://gomakethings.com/vanilla-javascript-version-of-jquery-extend/
var extend = function () {

    // Variables
    var extended = {};
    var deep = false;
    var i = 0;
    var length = arguments.length;

    // Check if a deep merge
    if ( Object.prototype.toString.call( arguments[0] ) === '[object Boolean]' ) {
        deep = arguments[0];
        i++;
    }

    // Merge the object into the extended object
    var merge = function (obj) {
        for ( var prop in obj ) {
            if ( Object.prototype.hasOwnProperty.call( obj, prop ) ) {
                // If deep merge and property is an object, merge properties
                if ( deep && Object.prototype.toString.call(obj[prop]) === '[object Object]' ) {
                    extended[prop] = extend( true, extended[prop], obj[prop] );
                } else {
                    extended[prop] = obj[prop];
                }
            }
        }
    };

    // Loop through each object and conduct a merge
    for ( ; i < length; i++ ) {
        var obj = arguments[i];
        merge(obj);
    }

    return extended;

};

//########################################################################################
//https://konklone.io/json/
//https://github.com/konklone/json/blob/gh-pages/assets/site.js
function parse_object(obj, path) {
    if (path == undefined)
        path = "";

    var type = typeof(obj);
    var scalar = (type == "number" || type == "string" || type == "boolean" || type == "null");

    if (type == "array" || type == "object") {
        var d = {};
        for (var i in obj) {

            var newD = parse_object(obj[i], path + i + "/");
            d = extend(d, newD);
        }

        return d;
    }

    else if (scalar) {
        var d = {};
        var endPath = path.substr(0, path.length-1);
        d[endPath] = obj;
        return d;
    }

    // ?
    else return {};
}

// otherwise, just find the first one
function arrayFrom(json) {
    var queue = [], next = json;
    while (next !== undefined) {
        if (typeof(next) == "array") {

            // but don't if it's just empty, or an array of scalars
            if (next.length > 0) {

              var type = typeof(next[0]);
              var scalar = (type == "number" || type == "string" || type == "boolean" || type == "null");

              if (!scalar)
                return next;
            }
        } if (typeof(next) == "object") {
          for (var key in next)
             queue.push(next[key]);
        }
        next = queue.shift();
    }
    // none found, consider the whole object a row
    return [json];
}

function removeTrailingComma(input) {
  if (input.slice(-1) == ",")
    return input.slice(0,-1);
  else
    return input;
}

function flatten(inArray) {
    var outArray = [];
    for (var row in inArray)
        outArray[outArray.length] = parse_object(inArray[row]);
    return outArray
}
//########################################################################################
//https://www.newline.co/@anthonygore/how-to-convert-json-to-csv-in-nodejs--23c6b226
function convert_to_csv(data){
    csv = data.map(row => Object.values(row));
    csv.unshift(Object.keys(data[0]));
    csv = csv.join('\n');
    console.log(csv)
    return csv
}
//########################################################################################
const dataSourceUrl = "https://raw.githubusercontent.com/datameet/covid19/master/data/mohfw_vaccination_status.json"
const data_json =  (await axios.get(dataSourceUrl)).data
const data = flatten(data_json.rows)
console.log(data)


$respond({
  immediate: true,
  status: 200,
  headers: {"Content-type":"text/plain"},
  body: convert_to_csv(data)
})