function getSheetData(workbook, sheetNumber, cellName) {
 var workbook = xlsx.readFile(workbook);
 var sheet_name = workbook.SheetNames[sheetNumber];
 var address_of_cell = cellName;
 var worksheet = workbook.Sheets[sheet_name];
 var desired_cell = worksheet[address_of_cell];
 var desired_value = desired_cell.v;
 return desired_value;
}

var data = getSheetData('1234.xlsx', 0, 'A1');
 console.log(data);

// in js file
res.render('example.jade', {
     data: getSheetData('1234.xlsx', 0, 'A1');
})

// in jade file
div=data

// in main js file
global.getSheetData = function(workbook, sheetNumber, cellName){
      // your code
}
// in jade file
div=getSheetData('1234.xlsx', 0, 'A1')