JAVASCRIPT

excel date to javascript date

// function to convert excel date to normal js date  
excelDateToJSDate(excelDate) {
    var date = new Date(Math.round((excelDate - (25567 + 1)) * 86400 * 1000));
    var converted_date = date.toISOString().split('T')[0];
    return converted_date;
}

convert excel date to javascript date

function ExcelDateToJSDate(serial) {
   var utc_days  = Math.floor(serial - 25569);
   var utc_value = utc_days * 86400;                                        
   var date_info = new Date(utc_value * 1000);

   var fractional_day = serial - Math.floor(serial) + 0.0000001;

   var total_seconds = Math.floor(86400 * fractional_day);

   var seconds = total_seconds % 60;

   total_seconds -= seconds;

   var hours = Math.floor(total_seconds / (60 * 60));
   var minutes = Math.floor(total_seconds / 60) % 60;

   return new Date(date_info.getFullYear(), date_info.getMonth(), date_info.getDate(), hours, minutes, seconds);
}

convert javascript date into excel date

var record_date = Date.parse(item.record_date_string)
var days = Math.round((record_date - new Date(1899, 11, 30)) / 8.64e7);
item.record_date = parseInt((days).toFixed(10));

return item;