calculate number of days between two dates iso code example

Example 1: subtracting two date objects in javacript

function findDayDifference(date1, date2) {
	// always round down
  return Math.floor((Math.abs(date2-date1))/(1000*60*60*24));
}

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