Develop Reference

How to change ISO date to Standard JS Date?

I am trying to change an ISO date to a Standard JS Date format. The JS format I am referring to is:
Mon `Jul 20 2020 14:29:52 GMT-0500 (Central Daylight Time)`
What is the best way to go about doing this? Thanks!

const ISO_DATE = '2020-07-14T23:02:27.713Z';
function formatDate(dateStr) {
const date = new Date(dateStr);
return date.toString();
};
console.log(formatDate(ISO_DATE));

One way is:
let isoDate = "2020-07-20T14:29:52Z";
var myDate = new Date(isoDate);
console.log(myDate.toString()); // Mon Jul 20 2020 17:29:52 GMT+0300 ( (your time zone)
console.log("Back to ISO Date: ", myDate .toISOString());
If you want to convert it back to ISO Date use:
console.log(myDate.toISOString());

If statement with date comparison

I'm trying to write an if statement that runs some code if the date is after April 24th, 2017, 10 am EDT, but it doesn't appear that my variables are comparable (different data types?).
I'm trying to avoid using Moment.js for just this.
var today = new Date();
var launch = 'Mon Apr 24 2017 10:00:00 GMT-0400 (EDT)';
today returns Tue Apr 04 2017 14:34:41 GMT-0400 (EDT).
When I test if either is greater than the other, both are false. How should I format my dates?
Thanks!

You have to have launch as a date type:
var today = new Date();
var launch = 'Mon Apr 24 2017 10:00:00 GMT-0400 (EDT)';
var launchDate = Date.parse(launch);
if ( launchDate > today )
You should also read more about dates here:
Compare two dates with JavaScript

date string that will ignore timezone offset

I am at (UTS-05:00) Eastern Time (US & Canada)
i.e, new Date().getTimezoneOffset() == 300 seconds.
Now, I have a API endpoint (JSON) that returns a date string like this.
{
someDate: '2016-01-01T00:40:00.000+00:00'
}
Here, I pass it to Date constructor like this
var dateString = "2016-01-01T00:40:00.000+00:00";
var someDay = new Date(dateString);
console.log(someDay)
Mozilla Firefox console shows
Date {Fri Jan 01 2016 00:40:00 GMT-0500 (Eastern Summer Time)}
Google Chrome console shows
Thu Dec 31 2015 19:40:00 GMT-0500 (Eastern Standard Time)
Chrome is taking the TimezoneOffset into consideration and Firefox is not. What can I do to get a Date that doesn't take Offset into consideration like FireFox in Chrome?

You can do it by:
var dates = '2016-01-01T00:40:00.000+00:00'.split(/-|T|:/);
var newDate = new Date(dates[0], dates[1]-1, dates[2], dates[3], dates[4]);

This hack works (not very clean, but does the job)
var dateString = '2016-07-27T01:40:30';
var dateParts = dateString.split(/-|T|:/);
var saneDate = new Date(
+dateParts[0],
dateParts[1] - 1,
+dateParts[2],
+dateParts[3],
+dateParts[4],
+dateParts[5]);
console.log(saneDate);

Javascript datetime format varying on different systems

I have a method to covert date to IST which is,
function GetCurrentIST() {
var dte = new Date();
dte.setTime(dte.getTime() + (dte.getTimezoneOffset() + parseInt(UtcOffset)) * 60 * 1000);
return dte.toLocaleString();
}
another function calls it like this,
function GetStartDate(Selected) {
var StartDt = new Date(GetCurrentIST());
StartDt.setDate(StartDt.getDate() + parseInt(Selected));
StartDt.setHours(0);
StartDt.setMinutes(0);
StartDt.setSeconds(0);
return StartDt;
}
The problem I'm facing is on my machine GetCurrentIST() returns date properly.
Eg. "10/12/2014, 12:26:37 PM"
and the StartDt I get as : Dec 10 2014 12:37:32 GMT+0530 (India Standard Time)
But on my friends machine GetCurrentIST() returns date as : "10/12/2014 12:28:40"
and StartDt as : Sun Oct 12 2014 12:29:09 GMT+0530 (India Standard Time)
Is this problem related to datetime format or something.
does anyone have any simple solution for this problem?

Get exact day from date string in Javascript

I have checked this SO post: Where can I find documentation on formatting a date in JavaScript?
Also I have looked into http://home.clara.net/shotover/datetest.htm
My string is: Mon Jun 24 2013 05:30:00 GMT+0530 (India Standard Time)
And I want to convert it to dd-mm-yyyy format.
I tried using:
var dateString = 'Mon Jun 24 2013 05:30:00 GMT+0530 (India Standard Time)';
var myDate = new Date(dateString);
var final_date = myDate.getDay()+"-"+(myDate.getMonth()+1)+"-"+myDate.getFullYear();
But it gives me the result as: 1-6-2013
The getDay() value is the index of day in a week.
For Instance,
If my dateString is Thu Jun 20 2013 05:30:00 GMT+0530 (India Standard Time)
it gives output as 4-6-2013
How can I get the proper value of Day?
P.S: I tried using .toLocaleString() and creating new date object from it. But it gives the same result.

To get the day of the month use getDate():
var final_date = myDate.getDate()+"-"+(myDate.getMonth()+1)+"-"+myDate.getFullYear();

W3 schools suggests just building your days of the week array and using it:
var d=new Date();
var weekday=new Array(7);
weekday[0]="Sunday";
weekday[1]="Monday";
weekday[2]="Tuesday";
weekday[3]="Wednesday";
weekday[4]="Thursday";
weekday[5]="Friday";
weekday[6]="Saturday";
var n = weekday[d.getDay()];
Not super elegant, but usable.

var dateString = 'Mon Jun 24 2013 05:30:00 GMT+0530 (India Standard Time)';
var myDate = new Date(dateString);
var final_date = myDate.getDate()+"-"+(myDate.getMonth()+1)+"-"+myDate.getFullYear();
Replace getDay() with getDate().
The above will return the local date for each date part, use the UTC variants if you need the universal time.

I think you will have to take an Array of the days & utilize it using the received index from the getDay() method.

To get required format with given date will achieve with moment.js.
a one liner solution is
import moment from "moment";
const date = new Date();
const finalDate = moment(date).format("DD-MM-YYYY")