JS: CSV File Creation Using BLOB

jsCSVFileCreationBlob.js

function exportToCsv(filename, rows) {
        var processRow = function (row) {
            var finalVal = '';
            for (var j = 0; j < row.length; j++) {
                var innerValue = row[j] === null ? '' : row[j].toString();
                if (row[j] instanceof Date) {
                    innerValue = row[j].toLocaleString();
                };
                var result = innerValue.replace(/"/g, '""');
                if (result.search(/("|,|\n)/g) >= 0)
                    result = '"' + result + '"';
                if (j > 0)
                    finalVal += ',';
                finalVal += result;
            }
            return finalVal + '\n';
        };

        var csvFile = '';
        for (var i = 0; i < rows.length; i++) {
            csvFile += processRow(rows[i]);
        }

        var blob = new Blob([csvFile], { type: 'text/csv;charset=utf-8;' });
        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.visibility = 'hidden';
                document.body.appendChild(link);
                link.click();
                document.body.removeChild(link);
            }
        }
    }

I created a csv from an object like this:

const csvData = data.reduce((prev, curr) => (prev += Object.values(curr).join(Delimiter) + "\n"), "");

const Delimiter = ","
and csvData is an array of objects.

You need to add headers too,
and then join csvData with csvHeaders with a delimiter.

const csv = `${csvHeaders}\n${csvData}`;

csvHeaders can be Object.keys(data[0]).join(Delimiter);

Don't forget to call URL.revokeObjectURL at the end.

Don't forget to call URL.revokeObjectURL at the end.

Why?

revokeObjectURL

Memory management is a thing.

https://developer.mozilla.org/en-US/docs/Web/API/URL/revokeObjectURL_static

"Call this method when you've finished using an object URL to let the browser know not to keep the reference to the file any longer."