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Convert date string to Postgres timestamp timezones format

I have the following date:
25-JAN-18 01.31.02 AM +00:00
and am trying to convert into a Postgres compatible timestamp with time zone format.
I am trying the following code to convert into the compatible format:
document.getElementById("parsedDate3").innerHTML = moment("25-JAN-18 01.31.02.923526 AM +00:00 ", "d-MMM-YY hh.mm.ss A Z");
But I am getting the output as
Mon Jan 01 2018 02:31:02 GMT+0100
Can anyone please help me with this.

You are using lower-case d which is for the day of the week, 0 (Sunday) through 6 (Saturday).
Use upper-case D instead, which is for the day of the month.
Note that Moment's formatting tokens are slightly different than in other libraries and languages, so check the chart in the docs carefully.
Also:
In your code you have 6 extra digits following the seconds. If you need to account for those, use SSSSSS. Otherwise they are ignored.
You shouldn't assign a Moment object directly to an HTML element's innerHTML property. Instead, call the .format() function on the Moment object first to generate a string. You can optionally pass an argument to this function, to control the output format.

You can simply do it in PostgreSQL:
SELECT to_timestamp('25-JAN-18 01.31.02.923526 AM +00:00', 'DD-MON-YY HH.MI.SS.US AM TZH:TZM');
to_timestamp
-------------------------------
2018-01-25 02:31:02.923526+01
(1 row)
This will work for PostgreSQL v11 or better.
Earlier versions of to_timestamp cannot parse the time zone information yet.
If you need it to work on 9.6, and you know that the time zone is always going to be +00:00, you could simple omit the TZH:TZM in the format string.

How can I create a Date from string, ignoring any timezone offsets?

The server uses +03:00 timezone. It offers me a date in this format: "2017-04-12T00:00:00+03:00"
I then create a new Date from this string:
options.startDate = new Date("2017-04-12T00:00:00+03:00")
But because on the client there is a different timezone, the result is actually:
Tue Apr 11 2017 23:00:00 GMT+0200 (Central Europe Daylight Time)
This brings me back one day and it's a big deal for me. Is there an elegant way to avoid this and create the same Date and Time in javascript, ignoring the timezone offset?

The date you have in options.startDate is the correct one. What you want is to display it as if you were from the same timezone as the server.
If you now server's timezone in the client script then I would considere using a library like moment.js. It would allow you to format date in the timezone you want (GMT for instance, or the one of the server).
Using both moment.js and its plugin timezone code could be :
moment("2017-04-12T00:00:00+03:00").tz("America/Los_Angeles").format();

You should never use the Date constructor or Date.parse to parse strings due to browsers differences. Even if you remove the timezone from the string and parse the remainder, e.g.
console.log( new Date('2017-04-12T00:00:00+03:00'.substr(0,19)).toString() );
you'll get different results in different browsers (e.g. Firefox and Safari).
If you don't want to use a library, use a simple function (see below). However, if you remove the timezone, the string will represent a different moment in time in each timezone with a different offset.
function parseISOIgnoreTimezone(s) {
var b = s.split(/\D/);
return new Date(b[0], b[1]-1, b[2], b[3], b[4], b[5]);
}
console.log(parseISOIgnoreTimezone('2017-04-12T00:00:00+03:00').toString());

I really recommend #VictorDrouin his answer.
But if for some reason you don't want moment.js or fiddle around with it you can use this 'hack'
new Date("2017-04-12T00:00:00+03:00".match(/\d{4}\-\d{2}\-\d{2}T\d{2}:\d{2}:\d{2}/).pop());
What it does it matches the date against given regex date format, and then supplies it to the date parser which makes it a date.
Be careful when supplying it back to the database that you supply it back without timezone offset.
var stringdate = "2017-04-12T00:00:00+03:00";
function getDate(str_date) {
var matched = str_date.match(/\d{4}\-\d{2}\-\d{2}T\d{2}:\d{2}:\d{2}/).pop();
return new Date(matched);
}
console.log(getDate(stringdate));

Convert ISO Date string to date in JavaScript

Need help to convert exactly from ISO Date string to Date:
I have an ISO string date: "2016-01-23T22:23:32.927".
But when I use new Date(dateString) to convert Date, the result is wrong:
var date = new Date("2016-01-23T22:23:32.927");
The result is: Sun Jan 24 2016 05:23:32 GMT+0700. It's not true. I want the date is 23 not 24.
Please help me. Thanks a lot!

You need to supply a timezone offset with your iso date. Since there isn't one, it assumes the date to be in GMT and when you log it out, it prints it in the timezone of your browser. I think that if you pass "2016-01-23T22:23:32.927+07:00" to new Date() you would get the value you are expecting.

JavaScript environments (browser, node,...) use a single timezone for formatting dates as strings. Usually this is your system's timezone. Based on the output you get, yours is GMT+0700.
So what happened:
The string you passed as ISO format to the Date constructor doesn't specify a timezone. In this case it is treated as UTC.
When you then output the date (I'll assume with console.log), it is converted to the timezone of your environment. In this case 7 hours where added.
If that doesn't suit you, you can change the way you output the date. This depends on what output you want, e.g.:
If you just want the UTC timezone again, you can use date.toISOString().
If you want to output it in another timezone, you can call date.getTimezoneOffset() and figure out the difference between both timezones. You'd then probably need to get the individual date parts and add/subtract the timezone difference accordingly. At this point you could consider using an existing library, taking into account their possible disadvantages.

If you're willing and able to add a dependency, I recommend using moment.js for this. It makes date handling in Javascript much more straightforward and a lot safer, and fixes your specific problem right out of the box.
To do this, 1st load it from a CDN, e.g. Moment.JS 2.14.1 minified. Then use it as follows:
var date = moment("2016-01-23T22:23:32.927");
console.log(date);
// output: Sat Jan 23 2016 22:23:32 GMT-0500
...i.e. your desired result :)
Here's a jsfiddle demonstrating this.

Use date.toUTCString()
it'll give you 23 instead of 24 as it Convert a date object to a string, according to universal time

How to change only timezone without modifying the time in momentz

I have date and time in 2016-06-21T10:00:00-07:00 format which represets 06/21/2016 5 PM in PST, I just want to change this to 06/21/2016 5 PM in EST and vice versa. How can I do it with momentz?
JSFiddle
debugger;
var dateTime = moment('2016-06-21T10:00:00-07:00');
var newDateTime = dateTime.clone();
newDateTime.tz('US/Eastern');
//dateTime = dateTime.utc();
console.log(dateTime.utcOffset());
console.log(newDateTime.utcOffset());
console.log(newDateTime.utcOffset() - dateTime.utcOffset());
//console.log(utc.format());
dateTime = dateTime.add(newDateTime.utcOffset(), 'minutes');
console.log(dateTime.format());
console.log(new Date(Date.parse(dateTime.format())).toJSON());
EDIT:
given input = 2016-06-21T08:00:00-07:00 (PST)
expected output = 2016-06-21T08:00:00-04:00 (EST)
So when I convert that to UTC then it should become
2016-06-22T15:00:00Z for PST
2016-06-22T12:00:00Z for EST

I think you are confused about how ISO8601 format works. This format always represents local time with a time zone offset. Thus 2016-06-21T10:00:00-07:00 represents June 21 2016 at 10 AM in a timezone that is currently UTC-7 (this could be US pacific, among many others).
It sounds like you want to take the local time, but put it in a new timezone. This opens up some interesting questions about why you are receiving the date in the format that you are. If the date is meant to be interpreted as an exact point on the global timeline, then the format you are receiving it in is good. If however, the date is meant to be interpreted as a local time (not relative to UTC), it might be worth considering the possibility that the format of the date needs to be changed at the source. For instance, if you are making an ajax request to an API, and it is returning a date in this format, but that date actually has no relationship to UTC, it would be good to try to change that API to only send the local time (without the offset). If you were able to do that, then the following code would work:
moment.tz('2016-06-21T10:00:00', 'America/New_York').format()
"2016-06-21T10:00:00-04:00"
If you are unable to do that, or if the date is meant to be interpreted as an exact point on the global timeline, but you wish to ignore that in your specific use case, that can be done. You will need to specify a parse format that ignores the timezone offset on your initial time stamp. The code would be as follows:
moment.tz('2016-06-21T10:00:00-07:00', 'YYYY-MM-DDTHH:mm:ss', 'America/New_York').format()
"2016-06-21T10:00:00-04:00"
You might benefit from the material in this blog post, as it covers how ISO8601 format works, and how all of moment's constructor functions work.

Checkout moment().utcOffset() You can pass in the offset as parameter to this function and the date would use that locale.
Assuming you know beforehand the utcOffsets required which in your case are -420 and -240 or -300(EST with DayLightSaving). Below can be done
var dateTime = moment('2016-06-21T10:00:00-07:00');
dateTime.utcOffset(-420).format();
"2016-06-21T10:00:00-07:00"
dateTime.utcOffset(-240).format()
"2016-06-21T13:00:00-04:00"
NOTE: With -04:00, it should 13:00:00 and not 07:00:00 - http://www.timeanddate.com/time/zones/est
EDIT: This answer was posted to the earlier version of question, where same time was needed in different timezones. If it is incorrect, kindly please elaborate on how it is.
Thanks!

Is there a simple conversion for this datetime format?

I'm retrieving data from a JSON feed using jQuery and as part of the feed I'm getting 'datetime' attributes like "2009-07-01 07:30:09". I want to put this information into a javascript Date object for easy use but I don't believe the Date object would recognize this kind of format if I simply plugged it into the constructor. Is there a function or maybe a clever trick I can use to quickly break down this format into something the Date object can recognize and use?

The "date" attribute you are retrieving from that webservice is not a real Date, as it is not a recognized date format.
The easiest way to handle it as a Date object would be to replace the empty space with a "T":
var receivedDate = "2009-07-01 07:30:09";
var serializedDate = new Date(receivedDate.replace(" ", "T"));
alert(serializedDate);
This is not the most correct, as it is not handling timezones, but in most cases will work.

See this and this.
input = "2009-07-01 07:30:09";
var res = input.match(/([\d\-]+) (\d+):(\d+):(\d+)/);
date = new Date(Date.parse(res[1]));
date.setHours(res[2]);
date.setMinutes(res[3]);
date.setSeconds(res[4]);
console.log(date);
Edit: My original answer was
t = new Date(Date.parse("2009-07-01 07:30:09"));
which did not throw any error in chrome but all the same incorrectly parsed the date. This threw me off. Date.parse indeed appears to be quite flaky and parsing the complete date and time with it is probably not very reliable.
Edit2: DateJS appears to be a good solution for when some serious parsing of text to date is needed but at 25 kb it is a bit heavy for casual use.

var str="2009-07-01 07:30:09";
It depends on the time zone,
and if the date string has subtracted 1 for the month.
If it is GMT time, and the 07 means July and not August:
var str="2009-07-01 07:30:09";
var d=new Date(), time;
str=str.split(/\D0?/);
str[1]-=1;
time=str.splice(3);
d.setUTCFullYear.apply(d,str);
d.setUTCHours.apply(d,time)
alert(d)
/* returned value: (Date)
Wed Jul 01 2009 03:30:09 GMT-0400 (Eastern Daylight Time) or local equivilent
*/

This may be a bit cumbersome, but the JavaScript Date object will take an argument list of YYYY,MM,DD,HH,MM,SS. Parse out the date value and pass it to a Date constructor, e.g.
var splitDT= '2009-07-01 07:30:09'.split(' '); // ['2009-07-01','07:30:09']
var d= splitDT[0].split('-');
var t= splitDT[1].split(':');
alert( (new Date(d[0],d[1],d[2],t[0],t[1],t[2])) );
Bah. Had to use the array index values instead. Yeah, that's a mess. But it works.