function makeFriendlyDates(arr) {
  var dateArr1 = arr[0].split('-');
  var mon1 = numberToMonth(parseInt(dateArr1[1]));
  var day1 = parseInt(dateArr1[2]) + getOrd(parseInt(dateArr1[2]));

  var dateArr2 = arr[1].split('-');
  var mon2 = numberToMonth(parseInt(dateArr2[1]));
  var day2 = parseInt(dateArr2[2]) + getOrd(parseInt(dateArr2[2]));

  var oneDay = 1000 * 60 * 60 * 24;

  var firstDate = new Date(parseInt(dateArr1[0]), parseInt(dateArr1[1]), parseInt(dateArr1[2]));
  var lastDate = new Date(parseInt(dateArr2[0]), parseInt(dateArr2[1]), parseInt(dateArr2[2]));

  var tempDate = Math.round( (lastDate.getTime() - firstDate.getTime()) / oneDay);

  if (tempDate === 0) {
  	return mon1 + " " + day1 + ", " + dateArr1[0];
  }

  var firstDateString = mon1 + " " + day1;
  var lastDateString;

  if (dateArr1[0] == dateArr2[0] && mon1 == mon2) {
  	lastDateString = day2;
  } else {
  	lastDateString = mon2 + " " + day2;
  }

  if (tempDate >= 365) {
  	lastDateString += ", " + dateArr2[0];
  }

  if (dateArr1[0] != '2016' || tempDate >= 365) {
  	firstDateString += ", " + dateArr1[0];
  }

  return [firstDateString, lastDateString];
}

function numberToMonth(num) {
	var monHash =  {1:'January', 2:'February',
					3:'March', 4:'April',
					5:'May', 6:'June',
					7:'July', 8:'August',
					9:'September', 10:'October',
					11:'November', 12:'December'};

	return monHash[num];
}

function getOrd(num) {
	if (num == 13 || num == 12 || num == 11) {
		return 'th';
	} else {
		num = num % 10;
	}
	switch(num) {
		case 1:
			return 'st';
		case 2:
			return 'nd';
		case 3:
			return 'rd';
		default:
			return 'th';
	}
}

makeFriendlyDates(["2018-01-13", "2018-01-13"]);