diffDateInHours.js

/*
    Helper functions to calculate difference in hours, minutes and seconds between two dates
*/

function diffMinutes(initial, final) {
	if(initial > final) return 59 + final - initial
	return final - initial
}

function getDiffTime(initialDate, finalDate) {
	return {
		hours  : Math.floor((finalDate - initialDate) / (1000 * 60 * 60)),
		minutes: diffMinutes(initialDate.getMinutes(), finalDate.getMinutes()),
		seconds: Math.abs(finalDate.getSeconds() - initialDate.getSeconds())
	}
}

// Testing
/*
	var releaseDate = new Date('2017-11-21T23:59:59')
	setInterval(function() {console.log(getDiffTime(new Date(), releaseDate))}, 1000)
*/