Button Handler to download some JSON as CSV

downloadjsonascsv.js

//bind onclick to downloadcsv.
//o should be the json you want to turn into a table
//h should be a string array for the header row, or this can be null and it will use the keys from the first record
//n is the name of the file, csv will be appended. if omitted it will just be 'data.csv'
export const downloadcsv = (o,h,n = 'data') => {
    downloadFile( toCSV(o,h) , n + '.csv', 'text/csv' );	
}
const toCSV = (o,h) => {
	const a = (v) => `"${v.join(`","`)}"`
	let csv = []
	csv.push(h ? h : Object.keys(o[0]));
	o.forEach(x=>csv.push(a(Object.values(x))))
	return csv.join("\n")
}
const downloadFile = (fileContents,fileName, fileType) => {

    var blob = new Blob([fileContents], { type: fileType });
    
    if (navigator.msSaveBlob) { // IE 10+
        navigator.msSaveBlob(blob, fileName);
    } else {
        var link = document.createElement("a");
        if (link.download !== undefined) { // feature detection
            // Browsers that support HTML5 download attribute
            var url = URL.createObjectURL(blob);
            link.setAttribute("href", url);
            link.setAttribute("download", fileName);
            link.style.display = "none";
            document.body.appendChild(link);
            link.click();
            document.body.removeChild(link);		
				}
    }
	
}