Utility (Data): Join Thing Metrics & Meta

var downloadCSV = (data, fileName) => {
		var d = document,
    a = d.createElement('a');
    a.href = window.URL.createObjectURL(new Blob([d3.csvFormat(data)],{type:'text/csv;charset=utf-8;'}));
    a.setAttribute('download', `${fileName}.csv`);
    d.body.appendChild(a);
    a.click();
    d.body.removeChild(a);
  };
(() => {
  var options = {
    scripts: ["https://d3js.org/d3.v5.min.js"],
  }

var run = (data) => {
    console.log(`Import Data by dropping files anywhere on the browser window. Export Data: downloadCSV(data, "fileName") `);
  }

const fileToString = (inputFile) => {
	const fr = new FileReader();
	return new Promise((resolve, reject) => {
		fr.onerror = () => {fr.abort(); reject({error:"file reader error"})}
		fr.onload = () => resolve(fr.result); 
		fr.readAsText(inputFile);
})}
var collections = [];
const dropHandler = async (e) => {
	e.preventDefault(); //disable default drop behavior
  for await (let file of e.dataTransfer.files) { //loop through dropped files
		let r = {format:file.name.slice(file.name.lastIndexOf(".")+1)}
		const str = await fileToString(file); //convert dropped file to string
		var parse = () => {
			var stringParser = () => {
				var parseStr = (delimiter) => str.split(delimiter);
				var testStr = (delimiter) => str.indexOf(delimiter) > -1
				var t = {hasLines:testStr("\n"),hasComma:testStr(","),hasTab:testStr("\t")};
				return t.hasLines ? parseStr("\n") : t.hasTab ? parseStr("\t") : t.hasComma ? parseStr(",") : [];
			}
			return r.format == "json" ? JSON.parse(str) :
			 r.format == "txt" ? stringParser() :
			 r.format == "csv" ? d3.csvParse(str) : []
		};
		r.name = file.name.replace("."+r.format,""),
		r.data = parse();

if(collections.length == 1){
			console.log("converting to object...")
			r.data = d3.nest().key(d => d.id).map(r.data);
			console.log("conversion complete...")
		}
		console.log({report:r}); 
		collections.push(r.data);
		if(collections.length == 2){
		console.log("Mapping...")
		var mergedData = collections[0].reduce((collection,a) => {
var b = collections[1]["$"+a.id];
if(b){
    delete a.fileName;
    delete b.fileName;
	collection.push({...b[0],...a})
}
return collection
},[]);
	downloadCSV(mergedData, "mergedData");
		}
		}
 }
window.ondragover = (e) => e.preventDefault(); //Prevent default browser behavior
window.ondrop = (e) => dropHandler(e); //Handle dropped files
const loadScripts = (scripts) => {
	console.log(`Loading External Scripts`);
	var scriptCountdown = scripts.length;
	var loadScript = (url) => {
		var scriptsLoaded = () => {
			scriptCountdown == 0 ? run() : null;
			return true;
		}
		var imported = document.createElement('script');
				imported.src = url;
				imported.addEventListener("load", () => {scriptCountdown--; scriptsLoaded();});
				document.head.appendChild(imported);
	}
	scripts.forEach(loadScript)
}
loadScripts(options.scripts);
})();