find milli until some date in the future

// Return milliseconds until a specified date string

function _parseDate(input) {

var re = /^(?:(?:(\d{1,2})[\/.\\-](\d{1,2})(?:[\/.\\-]((?:\d{2}|\d{4})))?(?:\D(\d{1,2}):(\d{1,2})(?::(\d{1,2}))?)?)|(?:(\d{1,2}):(\d{1,2})(?::(\d{1,2}))?))$/;

var time = re.exec(input);

var year, month, day, hour, minute, second;

var future, now;

var curDate = new Date();

var unixCurDayOfMonth = new Date(curDate.getFullYear(), curDate.getMonth(), curDate.getDate()).getTime();

var unixCurTime = curDate.getTime();

if (time) {

var yearIsNotDefined = (typeof time[3] === 'undefined');

var dateIsNotDefined = (typeof time[1] === 'undefined');

year = parseInt(time[3] || curDate.getFullYear(), 10);

if (year < 100) {

year += 2000;

}

month = parseInt(time[2] || curDate.getMonth()+1, 10);

day = parseInt(time[1] || curDate.getDate(), 10);

hour = parseInt(time[4] || time[7] || 0, 10);

minute = parseInt(time[5] || time[8] || 0, 10);

second = parseInt(time[6] || time[9] || 0, 10);

var unixReqTime = new Date(curDate.getFullYear(), curDate.getMonth(), curDate.getDate(), hour, minute, second).getTime();

if ((unixCurTime > unixReqTime) && dateIsNotDefined) {

day += 1;

}

var unixReqDayOfMonth = new Date(year, month-1, day).getTime();

var todayIsAfterRequestedDay = (unixCurDayOfMonth > unixReqDayOfMonth);

var todayIsSameAsRequestedDayButEarlierInTheDay = (unixReqDayOfMonth == unixCurDayOfMonth && unixReqTime < unixCurTime);

if ((todayIsAfterRequestedDay || todayIsSameAsRequestedDayButEarlierInTheDay) && yearIsNotDefined) {

year += 1;

}

future = new Date(year, month-1, day, hour, minute, second).getTime();

}

else {

future = 0;

}

now = Date.now();

if (future - now < 0) {

return 0;

}

else {

return future - now; // milli

}

}

var testcases = [

"18/10/2014 18:00:11", //0

"18/10/2014 18:00", //1

"18/10/2014@18:00", //2

"18/10@18:00:11", //3

"18/10T18:00", //4

"18/10/2015", //5

"18/10/04/18:00", //6 (should be 0)

"00:12", //7

"18/10", //8

"05/12 22:20", //9

"18/07T18:00" //10 (test summer time)

];

for (var i in testcases) {

console.log(i + ": " + _parseDate(testcases[i]));

}