JavaScript - Convert CSV to XLSX (Preferably Without Use of Library(s))
<p>As the title says, I currently have a CSV file created from SharePoint list data and in order to display this information as a spreadsheet, I want to convert it to an Excel XLSX file.  I prefer to do this without relying on a third-party library.  At first, I started to use ActiveX objects to try to recreate and/or save the CSV as XLSX, but there's a limitation with that since I can't really use it in other browsers besides IE.  I was thinking using Blob to somehow convert it?  That's where I'm stuck.</p>

<pre><code>function createCsv(data) {
    var result = "";

    if (data == null || data.length == 0) {
        return;
    }

    var columnDelimiter = ',';
    var lineDelimiter = '\n';

    var keys = Object.keys(data[0]);

    // spreadsheet header

    result += keys.join(columnDelimiter);
    result += lineDelimiter;

    // spreadsheet data

    data.forEach(function (obj) {
        var count = 0;

        keys.forEach(function (key) {
            if (count &gt; 0) {
                result += columnDelimiter;
            }

            result += obj[key];
            count++;               
        });

        result += lineDelimiter;
    });

    return result;
}

function downloadCsv(csv) {
    if (csv == null) {
        return;
    }

    var filename = "test.csv";

    csv = "data:text/csv;charset=utf-8," + csv;

    var data = encodeURI(csv);

    console.log(data);

    var link = document.getElementById('csv');
    link.setAttribute('href', data);
    link.setAttribute('download', filename);

    console.log(link);

    //displayCsv(csv);
}

function displayCsv() {
    // using test csv here
    var message = "data:text/csv;charset=utf-8, yo, hey, lol";
    //var fileType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
    var fileType = "application/msexcel";

    var csvFile = new Blob([message], {type: fileType});
    var csvUrl = URL.createObjectURL(csvFile);

    console.log(csvFile);
    console.log(csvUrl);

}
</code></pre>

<p>CSV works fine with using the spreadsheet (by downloading and opening it in Excel), but I really need a way to display it as a spreadsheet on a webpage and not as text, so that's why I'm looking to convert it over.  Since I'm using this within SharePoint then I can use a Excel web part to display the XLSX - it won't open CSV files like this though. Thanks in advance.</p>