function dateNum(v, date1904) {

if(date1904) v+=1462;

var epoch = Date.parse(v);

return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);

}

function createSheet(data, opts) {

var ws = {};

var range = {s: {c:10000000, r:10000000}, e: {c:0, r:0 }};

for(var R = 0; R != data.length; ++R) {

for(var C = 0; C != data[R].length; ++C) {

if(range.s.r > R) range.s.r = R;

if(range.s.c > C) range.s.c = C;

if(range.e.r < R) range.e.r = R;

if(range.e.c < C) range.e.c = C;

var cell = {v: data[R][C] };

if(cell.v == null) continue;

var cell_ref = XLSX.utils.encode_cell({c:C,r:R});

if(typeof cell.v === 'number') cell.t = 'n';

else if(typeof cell.v === 'boolean') cell.t = 'b';

else if(cell.v instanceof Date) {

cell.t = 'n'; cell.z = XLSX.SSF._table[14];

cell.v = dateNum(cell.v);

}

else cell.t = 's';

ws[cell_ref] = cell;

}

}

if(range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range);

return ws;

}

function Workbook() {

if(!(this instanceof Workbook)) return new Workbook();

this.SheetNames = [];

this.Sheets = {};

}

function string2ArrayBuffer(s) {

var buf = new ArrayBuffer(s.length);

var view = new Uint8Array(buf);

for (var i=0; i!=s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;

return buf;

}

function export2xlsx (data, name) {

var wb = new Workbook(),

ws = createSheet(data);

wb.SheetNames.push(name);

wb.Sheets[name] = ws;

var wopts = { bookType:'xlsx', bookSST:false, type:'binary' };

var wbout = XLSX.write(wb,wopts);

saveAs(new Blob([string2ArrayBuffer(wbout)],

{type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"}),

name + ".xlsx");

}