var filename = "write.xlsx";
var data = [[1,2,3],[true, false, null, "sheetjs"],["foo","bar",new Date("2014-02-19T14:30Z"), "0.3"], ["baz", null, "qux"]]
var ws_name = "SheetJS";
if(typeof console !== 'undefined') console.log(new Date());
var wb = XLSX.utils.book_new(), ws = XLSX.utils.aoa_to_sheet(data);
XLSX.utils.book_append_sheet(wb, ws, ws_name);
if(typeof console !== 'undefined') console.log(new Date());
XLSX.writeFile(wb, filename);
if(typeof console !== 'undefined') console.log(new Date());
console