how to get difference 2 dates in javascirpt code example

Example 1: how to calculate the number of days between two dates in javascript

function javascript (date1, date2) {
   let oned = 24 * 60 * 60 * 1000;
   return Math.ceil((date2 - date1) / oned);
}

function javascript(date1, date2) {
	return new Date(date2 - date1).getDate() - 1
}

function javascript(date1, date2) {
  return Math.ceil((date2 - date1) / 8.64e7);
}

Example 2: javascript difference between two dates in days

const diffDays = (date, otherDate) => Math.ceil(Math.abs(date - otherDate) / (1000 * 60 * 60 * 24));

// Example
diffDays(new Date('2014-12-19'), new Date('2020-01-01'));   // 1839