Displaying estimated shipping delivery date (based on client's shipping criteria)

estimatedDeliveryTime.js

function estimatedDeliveryTime(){
	var timeStamp_1 = new Date(),
		timeStamp_2 = new Date(),
		dayNames = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"],
		monthNames = ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],
		estOffset = -240, // EST offset in minutes
		customerTimezoneOffset = timeStamp_1.getTimezoneOffset(),
		utc = (timeStamp_1.getHours() * 60) + timeStamp_1.getMinutes() + customerTimezoneOffset,
		customerEstTime = utc + estOffset, // Customer time in EST
		shippingCutoffTime = 16 * 60; // 4pm EST in minutes

	if (customerEstTime <= shippingCutoffTime) {
		orderDate = timeStamp_1.getDate();
		orderDay = timeStamp_1.getDay();
		timeTillCutoff = shippingCutoffTime - customerEstTime;
	} else {
		orderDate = timeStamp_1.getDate() + 1;
		orderDay = timeStamp_1.getDay() + 1;
		timeTillCutoff = shippingCutoffTime - customerEstTime + 1440;
	}

	nextDeliveryDay = orderDay + 1;
	nextDeliveryDay = ( nextDeliveryDay > 6 ) ? nextDeliveryDay - 7 : nextDeliveryDay;

	if (customerEstTime <= shippingCutoffTime) {
		nextDeliveryDayString = ( nextDeliveryDay == 0 || nextDeliveryDay == 6 ) ? 'Monday' : 'tomorrow';
	} else {
		nextDeliveryDayString = ( nextDeliveryDay == 0 || nextDeliveryDay == 6 ) ? 'Monday' : dayNames[nextDeliveryDay];
	}

	// Delivery date estimation
	if (orderDay == 4 || orderDay == 5) {
		deliveryEarliestDate = orderDate + 4;
		deliveryLatestDate = deliveryEarliestDate + 3;
	} else if (orderDay == 6) {
		deliveryEarliestDate = orderDate + 5;
		deliveryLatestDate = deliveryEarliestDate + 5;
	} else if (orderDay == 0) {
		deliveryEarliestDate = orderDate + 4;
		deliveryLatestDate = deliveryEarliestDate + 5;
	} else {
		deliveryEarliestDate = orderDate + 3;
		deliveryLatestDate = deliveryEarliestDate + 5;
	}

	deliveryEarliestDate = timeStamp_1.setDate(deliveryEarliestDate);
	deliveryEarliestDate = timeStamp_1.getDate();
	deliveryEarliestMonth = monthNames[timeStamp_1.getMonth()];
	deliveryEarliestDay = dayNames[timeStamp_1.getDay()];
	deliveryEarliest = deliveryEarliestDay + ', ' + deliveryEarliestMonth + ' ' + deliveryEarliestDate;

	deliveryLatestDate = timeStamp_2.setDate(deliveryLatestDate);
	deliveryLatestDate = timeStamp_2.getDate();
	deliveryLatestMonth = monthNames[timeStamp_2.getMonth()];
	deliveryLatestDay = dayNames[timeStamp_2.getDay()];
	deliveryLatest = deliveryLatestDay + ', ' + deliveryLatestMonth + ' ' + deliveryLatestDate;

	// Display information
	$('.next-delivery-day').html(nextDeliveryDayString);
	$('.delivery-date-range').html(deliveryEarliest + ' - ' + deliveryLatest);
	$('.delivery-cutoff-counter').html(minutesToHM(timeTillCutoff));
}