I am using this function to create a copy of my excel file named mytest.xlsx
i have merged cells with borders inside it but in the new file (the copy) some of the merged cells lost their borders i don't know why?

function createExce()
{
workbook.xlsx.readFile('mytest.xlsx')
.then(function(workbook) {
// use workbook
return workbook.xlsx.writeFile('new.xlsx');
});

}