function formatCSV(data) {
    return data.reduce(
        (csv, lineCells) => {
            let line = lineCells.reduce(
                (lineText, cell, idx) => {
                    cell = '"' + cell.trim().replace(/"/g, '""') + '"';
                    return lineText + cell + (idx == lineCells.length - 1 ? "" : ",")
                }, "");
            return csv + line + "\n";
        },
        ""
    );
}

function saveFile(data, mimeType, fileName) {
    fileName = fileName || document.title || "result";
    var blob;
    if (typeof window.Blob == "function") {
        blob = new Blob([data], {
            type: mimeType
        })
    } else {
        var BlobBuiler = window.BlobBuilder || window.MozBlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder;
        var builer = new BlobBuiler();
        builer.append(data);
        blob = builer.getBlob(mimeType)
    }
    var URL = window.URL || window.webkitURL;
    var url = URL.createObjectURL(blob);
    var link = document.createElement("a");
    if ('download' in link) {
        link.style.visibility = "hidden";
        link.href = url;
        link.download = fileName;
        document.body.appendChild(link);
        var j = document.createEvent("MouseEvents");
        j.initEvent("click", true, true);
        link.dispatchEvent(j);
        document.body.removeChild(link)
    } else if (navigator.msSaveBlob) {
        navigator.msSaveBlob(blob, fileName)
    } else {
        location.href = url
    }
}

function saveFileAsk(data) {
    let csv = formatCSV(data.slice(1, 50)).trim() || "- Empty -";
    if (confirm(`Click confirm to download if the sample data looks good (${data.length-1} items)：\n\n${csv}`)) {
        csv = formatCSV(data);
        saveFile(csv, "text/csv");
    }
}