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How to add today's time to any date object and getISOString?

I have a ngbDatePicker which helps me to pick a date. Then it returns an object like this:
{year:2020,month:12,day:03}
I'd like to get an ISOString of this date with today's time(current). So if time is 18:42 I should be able to get something like this:
2020-12-03T18:42:00.000Z
To do that I parsed object and made date firstly
(model is the object holds date like above)
var date = new Date(this.model.year + "-" + this.model.month + "-" + this.model.day);
//then to add today's time I found solution below on the internet whcih didn't work for me
var date2 = new Date(date);
var isoDateTime = new Date(date2 .getTime() - (date2 .getTimezoneOffset() * 60000)).toISOString();
Here isoDateTime returns 2020-12-10T03:00:00.000Z which is not I want.
How to solve this?
Working stackblitz

Just take the time part of a Date object and combine it with this.model:
var date2 = new Date();
var date = new Date(this.model.year, this.model.month-1, this.model.day,
date2.getHours(), date2.getMinutes(), date2.getSeconds());
var isoDateTime = date.toISOString();
console.log(isoDateTime);
The month parameter is 0 based, so we have to substract 1 from the month.
Result (I chose Dec.1st 2020 in the Datepicker):
2020-12-01T19:22:42.000Z
Try on Stackblitz

You can create a single Date for the time and append it to values from the object:
function myISOString(obj) {
let z = n=>('0'+n).slice(-2);
return `${obj.year}-${z(obj.month)}-${z(obj.day)}T${new Date().toTimeString().substring(0,8)}`;
}
let obj = {year:2020, month:12, day: 3};
console.log(myISOString(obj));
PS the use of leading zeros like 03 for numbers should be avoided as once upon a time that notation indicated octal values (but not any more), so 09 might be confusing.

Parsing a date in javascript

First of all thanks in advance for helping, the community is great.
I have a problem parsing my date and time. Here is my code:
var date = mail.bodyText.match(/\=\= date \=\=\s*(.*[^\s*])/);
if (date) {
var string1 = date[1].match(/^\d{4}\-\d{2}-\d{2}/);
var string2 = date[2].match(\s(\d{2}\:\d{2}\:\d{2}));
var string3 = date[3].match(\s(\+\d{4}));
var parts1 = string1.split("-");
var parts2 = string2.split(":");
if (parts1 && parts2)
{
var dt = new Date(parseInt(parts1[0], 10), parseInt(parts1[1], 10) - 1, parseInt(parts1[2], 10), parseInt(parts2[3], 10), parseInt(parts2[4], 10), parseInt(parts2[5], 10));
}
date_final = dt;
}
date_final is defined elsewhere, and is in Date Time Picker format, and here is the input I am trying to parse:
blabla
== date ==
2016-02-13 16:22:10 +0200
blabla
Every time I execute the code, I get a parsing problem. The variable date_final cannot handle the parsed date. What do you think is missing from this code?
Update:
Here is what I'v etried out. Impossible for me to locate what's wrong:
var date = mail.bodyText.match(/\=\= date \=\=\s*(.*[^\s*])/);
if (date) {
var initial = date[1];
var formated = initial.substring(0, 19);
var final = formated.replace(/-/g, '/');
var last = new Date(final);
Field = last;
logging += "{date=" + Field + "}";
}
The code is actually parsing an email and sending the result over SSL. What surprises me the most is that the logs keep posting the following output of the date i naddition to the "parsing issue": date=Sat Feb 27 2016 16:22:10 GMT+0200 (CEST).
Do you think the problem comes from the code or could be related to how the appliance this code implemented on can handle it?
Thanks
Jane

Sorry for answering in comment.
Here's one solution to your question:
var dateStr = '2016-02-13 16:22:10 +0200';
// get yyyy-MM-dd HH:mm:ss
var formatedStr = dateStr.substring(0, 19);
// get yyyy/MM/dd HH:mm:ss in case of working on most of the browsers
var finalStr = formatedStr.replace(/-/g, '/');
// Date object can easily parse the datetime string we formated above
var date = new Date(finalStr);

Date object can parse complex strings.
Mail providers usually follow an RFC on how timestamps should be written, thus allowing other programming languages to heavily support it.
Just pass your string into date object and it will convert it for you.
let mailStr = `blabla
== date ==
2016-02-13 16:22:10 +0200
blabla`;
let regex = mailStr.match(/\=\= date \=\=\s*(.*[^\s*])/);
let dt = new Date(regex[1]);
console.log(dt);
The output is described in ISO-8601

Reading the date from textbox as a string and converting it into as Date

I am reading the date from textbox by using javascript and trying to convert it as Date object.But my problem is date is converting as month and month is converting as date when converting the string to date.
Example:
03/12/2014 the value in the textbox
Actual Output:
03 as March,
12 as date (Its wrong)
Expected Output:
03 as date
12 as December (I am expecting)
While converting this string to date by using following snippet
var startTime = document.getElementById("meeting:startTime");
date.js
var stringToDate_startTime=new Date(Date.parse(startTime.value,"dd/mm/yy"));
moment.js
var date1=moment(startTime.value).format('DD-MM-YYYY');
In the above even i have used date.js and moment.js files also.But those also did not solve my problem.Please can anyone help me out to get rid out of this.

Try ...
var from = startTime.value.split("/");
var newDate = newDate(from[2], from[1] - 1, from[0]);
... assuming time included ...
var date_only = startTime.value.split("");
var from = date_only[0].split("/");
var newDate = newDate(from[2], from[1] - 1, from[0]);

I am not aware of an implementation of the Date.parse() method that accepts two arguments. You can view the Mozilla Date.parse() method description here Date.parse() - JavaScript | MDN.
It might be worth looking at the question/answer of this question for some more information: Why does Date.parse give incorrect results?
The next best option would be to split the date using String.split() and to rearrange the date parts
var dateStr = '03/12/2014 23:05';
var newDateStr = null;
var dateParts = dateStr.split('/');
if (dateParts.length == 3) {
var day = dateParts[0];
var month = dateParts[1];
var yearAndTime = dateParts[2];
// Rearrange the month and day and rejoin the date "12/03/2014 23:05"
newDateStr = [ month, day, yearAndTime].join('/');
} else {
throw new Error('Date not in the expected format.');
}
var date = new Date(newDateStr); // JS Engine will parse the string automagically
alert(date);
This isn't the most elegant solution, but hopefully that helps.

Subtracting Date time value

I have the upload date for a course saved in a ViewModel variable #Model.Course.UploadDate when calling the following code:
alert('#Model.Course.UploadDate');
I get an output as expected of:
21/01/2014 16:16:13
I know want to check that the uploadDate is within the last 10 seconds before sending a statement to the database but trying to use the following code:
var uploadDate = new Date('#Model.Course.UploadDate.ToLongDateString()');
alert("UPLOAD DATE " + uploadDate);
I get an unexpected output of:
Tue Jan 21 2013 00:00:00 GMT+0000
This is the format that I need the date in only with the saved time data shown. I am then looking to perform a calculation as follows:
var TENSECONDS = 10 * 1000;
var uploadDate = new Date('#Model.Course.UploadDate.ToLongDateString()');
var today = new Date();
var check = today - uploadDate;
if (parseInt(check) > parseInt(TENSECONDS))
alert("ROUTE1");
else
alert("ROUTE2");

Quote from the documentation of the Date object constructor:
value: Integer value representing the number of milliseconds since 1
January 1970 00:00:00 UTC (Unix Epoch).
So actually that's the safest thing to pass to the constructor of a Date object instead of some strings which might be incorrectly interpreted and are completely culture dependent.
So just convert your DateTime instance to the number of milliseconds that elapsed since 1 January 1970 and feed this timestamp to the constructor:
var timestamp = #(Model.Course.UploadDate - new DateTime(1970, 1, 1)).TotalSeconds;
var uploadDate = new Date(timestamp);
As an alternative you could use the ISO8601 format if you intend to be passing a string:
dateString: String value representing a date. The string should be in
a format recognized by the Date.parse() method (IETF-compliant RFC
2822 timestamps and also a version of ISO8601).
So:
var uploadDate = new Date('#Model.Course.UploadDate.ToString("o")');

I solved this using the following code:
var dateArray = new Array();
dateArray = '#Model.Course.UploadDate'.split("/");
var dateD = dateArray[0];
var dateM = dateArray[1];
var dateY = dateArray[2];
var dateT = dateArray[3];
timeArray = dateT.split(":");
var timeH = timeArray[0];
var timeM = timeArray[1];
var timeS = timeArray[2];
var dateUS = dateM + "/" + dateD + "/" + dateY + dateT;
var uploadDate = new Date(dateD,dateM,dateY,timeH,timeM,timeS);

Javascript JSON Date parse in IE7/IE8 returns NaN

I'm parsing a date from a JSON event feed - but the date shows "NaN" in IE7/8:
// Variable from JSON feed (using JQuery's $.getJSON)
var start_time = '2012-06-24T17:00:00-07:00';
// How I'm currently extracting the Month & Day
var d = new Date(start_time);
var month = d.getMonth();
var day = d.getDate();
document.write(month+'/'+day);// "6/24" in most browsers, "Nan/Nan" in IE7/8
What am I doing wrong? Thanks!

In older browsers, you can write a function that will parse the string for you.
This one creates a Date.fromISO method- if the browser can natively get the correct date from an ISO string, the native method is used.
Some browsers got it partly right, but returned the wrong timezone, so just checking for NaN may not do.
Polyfill:
(function(){
var D= new Date('2011-06-02T09:34:29+02:00');
if(!D || +D!== 1307000069000){
Date.fromISO= function(s){
var day, tz,
rx=/^(\d{4}\-\d\d\-\d\d([tT ][\d:\.]*)?)([zZ]|([+\-])(\d\d):(\d\d))?$/,
p= rx.exec(s) || [];
if(p[1]){
day= p[1].split(/\D/);
for(var i= 0, L= day.length; i<L; i++){
day[i]= parseInt(day[i], 10) || 0;
};
day[1]-= 1;
day= new Date(Date.UTC.apply(Date, day));
if(!day.getDate()) return NaN;
if(p[5]){
tz= (parseInt(p[5], 10)*60);
if(p[6]) tz+= parseInt(p[6], 10);
if(p[4]== '+') tz*= -1;
if(tz) day.setUTCMinutes(day.getUTCMinutes()+ tz);
}
return day;
}
return NaN;
}
}
else{
Date.fromISO= function(s){
return new Date(s);
}
}
})()
Result:
var start_time = '2012-06-24T17:00:00-07:00';
var d = Date.fromISO(start_time);
var month = d.getMonth();
var day = d.getDate();
alert(++month+' '+day); // returns months from 1-12

For ie7/8 i just did:
var ds = yourdatestring;
ds = ds.replace(/-/g, '/');
ds = ds.replace('T', ' ');
ds = ds.replace(/(\+[0-9]{2})(\:)([0-9]{2}$)/, ' UTC\$1\$3');
date = new Date(ds);
This replaces all occurrences of "-" with "/", time marker "T" with a space and replaces timezone information with an IE-friendly string which enables IE7/8 to parse Dates from Strings correctly. Solved all issues for me.

See RobG's post at Result of toJSON() on a date is different between IE8 and IE9+.
Below function worked for me in IE 8 and below.
// parse ISO format date like 2013-05-06T22:00:00.000Z
function convertDateFromISO(s) {
s = s.split(/\D/);
return new Date(Date.UTC(s[0], --s[1]||'', s[2]||'', s[3]||'', s[4]||'', s[5]||'', s[6]||''))
}
You can test like below:
var currentTime = new Date(convertDateFromISO('2013-05-06T22:00:00.000Z')).getTime();
alert(currentTime);

I suggest http://momentjs.com/ for cross browser date issues.

#gib Thanks for the suggestion on Moment.js. This small library really helps out with dealing with dates and JavaScript.
Moment.js solved the problem described in the original question that I was also having. IE8 was displaying JSON ISO dates as NaN when parsed into a new Date() object.
Quick solution (include moment.js in your page, or copy the code to your js functions include)
If you just need to display a date on your page, loaded from a JSON ISO date, do this:
order_date = moment(data.OrderDate); //create a "moment" variable, from the "data" object in your JSON function in Protoype or jQuery, etc.
$('#divOrderDate).html(order_date.calendar()); //use Moment's relative date function to display "today", "yesterday", etc.
or
order_date = moment(data.OrderDate); //create a "moment" variable, from the "data" object in your JSON function in Protoype or jQuery, etc.
$('#divOrderDate).html(order_date.format('m/d/YYYY')); //use Moment's format function to display "2/6/2015" or "10/19/2014", etc.
If you must have a Date() object (say for use with jQuery Components), do the following so successfully populate your JSON provided ISO date. (This assumes you are already inside the function of handling your JSON data.)
var ship_date = new Date(moment(data.ShipDate).format('m/d/YYYY')); //This will successfully parse the ISO date into JavaScript's Date() object working perfectly in FF, Chrome, and IE8.
//initialize your Calendar component with the "ship_date" variable, and you won't see NaN again.