convert js date to excel date code example

Example 1: excel date to javascript date

/use excel-date-to-js

//Description
//Converts Excel date in integer format into JS date.
//Dates are stored as numbers in Excel
//and count the number of days since January 0, 1900 (1900 standard, for mac it is 1904, which means January 0, 1904 is the start date).
//Times are handled internally as numbers between 0 and 1.

//Install
//npm install -s excel-date-to-js
//Usage
const { getJsDateFromExcel } = require("excel-date-to-js");
getJsDateFromExcel("42510");
// 2016-05-20T00:00:00.000Z

Example 2: 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);
}