Develop Reference

Dates (Assigning them depending on region)

var d = new Date();
"**Zone** - `" +
d.toTimeString().replace(/\d+:\d+:\d+\s+/, '').replace(/[G][M][T].\d+/, '') +
"` **Time** - " +
"`" + d.toLocaleTimeString() +
"` **Date** - " + "`" +
d.toLocaleDateString() + "`"
This is a string of mine which tells me the region, time and date. I am using it on a discord bot and am attempting to make them be different depending on the user's region. I'm not sure how to accomplish this, but for visual example...
The code stated above returns me -
Zone - (AUS Eastern Standard Time) Time - 16:49:28 Date - 2018-5-18
which I am satisfied with, however, for a test I got a foreign friend to hop on and it sent the same thing when what I am trying to make the result be is their region so...
Zone - (AMERICA Western Standard Time) Time - 02:29:09 Date - 2018-5-18
Anybody have any ideas?
EDIT: Within a new project of mine, I discovered the user of Intl.DateTimeFormat() which essentially returns an Array. There is an instance method for this function known as .resolvedOptions(), returning an object that has many values within. I simply went ahead and added .timezone which returned something similar to "Australia/Queensland".
var region = Intl.DateTimeFormat().resolvedOptions().timeZone;

I am assuming this code is run in a browser, and not in a server.
You cannot depend on d.toTimeString() and cutting out the timezone part to find a timezone, toTimeString can return different formats on different browsers. The specs has left the formatting to browser vendors.
You can get the timezoneOffset and map it to the timezone name, but wait, there is an issue. This may conflict with Day Light Savings time setting for regions. So you will need a historical set of data for Daylight Savings time all over world.
If you really want to do this, use moment with timezones, which can do the lookup for you and they have already created all mappings including DST for you.

Formatting milliseconds as date in couchDB map function

i am trying to convert milliseconds to my desired date format. But the format that i give to the function doesn`t seem to work.
In my map function
var date = new Date(item.showTime);
var dateString = date.toString('MM/dd/yy HH:mm:ss');
emit([doc.vehicleNumber,doc.advertId],{"seatNumber":item.seatNumber,"showTime":dateString ,"skipTime":item.skipTime});
});
The result is
{seatNumber: 2, showTime: "Tue Nov 21 2017 10:08:56 GMT+0000 (UTC)", skipTime: 0}
I need show time to in format of 10/12/2017 10:08:56.. I don`t know why this is not working.
Btw this is not javascript, i think it is about couchdb so please do
not mark this as duplicate with other JS questions.

CouchDB supports the use of CommonJS Modules in the map function definition.
http://docs.couchdb.org/en/2.1.1/query-server/javascript.html#commonjs
The problem is that modules should be defined in the design document and can not be loaded from external resources.
You can use standard JavaScript built-in objects and functions in your map function as couchjs is based in Mozilla's SpiderMonkey JS interpreter. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date
There is not base support in CouchDB JS runtime for date formating. You should write your own logic for this purpose.
If this is a big issue for you, you may try to hack the /path/to/couchdb/share/server/main.js file which is the one that sets the execution contexts of your functions, but I don't see it too much recommendable.

Parse the date and format it yourself. It's not difficult.
var date = new Date(Date.parse(item.showTime));
var timestring = "" + date.getMonth() + "/" + date.getDate() + "/" +
date.getFullYear() + " " + date.toTimeString().substr(0,8)

This is very much about JavaScript. The .toString() method does not take any formatting parameters. You can write your own function to convert the output, or you can use a library that does what you want.

Date and time parsing in JavaScript

I have a question that I am trying to solve for whole day.
I have Date and Time from Oracle DB that is shown on html page. I have jstl date formatter that has special pattern to show it. Let's take an example 09.05.2017 17:35 +0500 and pattern MM.dd.yyyy HH:mm Z. And I am getting it as String with jQuery . The first case: how to convert it to Date type without any changes. I tryed var date = new Date('09.05.2017 17:35 +0500') but if I have another time zone I'll recieve another UTC and time(hour) or maybe month etc.
Second: how to convert this time to UTC+0300.
I know one solution of this cases, but I think it's not easy. As I have constant pattern of Date, I can always parse the string and to write huge logic for solving second case. I am bad in JS and will be grateful for solution.

Regarding the parsing question, that is answered at Why does Date.parse give incorrect results? The bottom line is that you should parse the string manually and not rely on the built-in parser. A library can help, but if you only have one or two formats to deal with, writing your own parser isn't too difficult.
As for presenting time in a particular timezone, the same advice applies. If you always want UTC+0300, then start by knowing that javascript Dates are always UTC internally and have UTC methods to access those values. So you just change the UTC time by the required offset and format the date as required.
For formatting, see Where can I find documentation on formatting a date in JavaScript?
An example of adjusting the timezone:
// Return a string for UTC+0300 for the supplied date
// in dd-mm-yyyy hh:mm:ss format
function getUTC03(date) {
// Helper to pad with leading zero
function z(n){return ('0'+n).slice(-2)}
// Copy the date so don't affect original
var d = new Date(+date);
// Set UTC time to required offset
d.setUTCHours(d.getUTCHours() + 3);
// Format using UTC methods
return z(d.getUTCDate()) + '-' +
z(d.getUTCMonth()+1) + '-' +
d.getUTCFullYear() + ' ' +
z(d.getUTCHours()) + ':' +
z(d.getUTCMinutes()) + ':' +
z(d.getUTCSeconds()) + ' ' +
'+0300';
}
console.log('Currently at +0300 it\'s ' + getUTC03(new Date()));
However, many places observe daylight saving. To adjust for that, a library is helpful. You just need to provide a location for which the offset can be determined for any particular date and time. Again, there are many questions here about that too.

Use jQuery to Read Text then Change

I am using a CMS that generates some code for me. I am having the CMS auto-generate the date a page was last updated. (Note: This page contains information that is time sensitive and it is beneficial for the end user to see when the page was last updated.)
The system generates the following time stamp: 24-May-2013 11:54 AM, however, I would prefer the date to look like so: May 24, 2013 (to follow the US Standard way of writing time) and drop the time completely.
The code looks like so:
<p>Last Updated: <span class="time">24-May-2013 11:54 AM</span></p>
I believe this would be possible using jQuery but I do not know how to do this. Any recommendations on how to use jQuery to do this would be welcome!

$(".time").each(function() {
var $this = $(this),
// regex to retrieve day, month and year
stamp = /([0-9]{1,2})-([a-z]*)-([0-9]{4})/i.exec($this.text())
$this.html(stamp[2] + " " + stamp[1] + ", " + stamp[3]);
});
See the jsfiddle for demo: http://jsfiddle.net/mifeng/gquhp/

If you have jQuery UI, you can use datepicker.
$(".time").val($.datepicker.formatDate('M dd yy', new Date()));

strptime in Javascript

I have a date input field that allows the user to enter in a date and I need to validate this input (I already have server side validation), but the trick is that the format is locale dependent. I already have a system for translating the strptime format string to the the user's preference and I would like to use this same format for validating on the Javascript side.
Any ideas or links to a strptime() implementation in Javascript?

After a few days of googling I found this implementation which, although not complete, seems to handle all of the cases I have right now.

I've just added our php.js implementation of strptime(); I've tested it a bit, but it needs further unit testing. Anyhow, feel free to give it a shot; it should cover everything that PHP does (except for not yet supporting the undocumented %E... (alternative locale format) specifiers).
Note that it also depends on our implementation of setlocale() and array_map()...
https://github.com/kvz/phpjs/blob/master/functions/strings/setlocale.js
https://github.com/kvz/phpjs/blob/master/functions/array/array_map.js

Here is an example function that duplicates most of the functionality of strptime. The JavaScript date object generally will parse any date string you throw at it so you don't have to worry to much about that. So once you have a date object based off of your string you just push each element into a JS object and return it. This site has a good reference to the properties of the JavaScript date object: http://www.javascriptkit.com/jsref/date.shtml
function strptime(dateString){
var myDate = new Date(dateString);
return {tm_sec:myDate.getSeconds(),
tm_min: myDate.getMinutes(),
tm_hour: myDate.getHours(),
tm_mday: myDate.getDate(),
tm_mon: myDate.getMonth(),
tm_year: myDate.getFullYear().toString().substring(2),
tm_wday: myDate.getDay()};
}
var dateString = "October 12, 1988 13:14:00";
dateObj = strptime(dateString);
document.write("d:" + dateObj.tm_min + "/" + dateObj.tm_hour + "/" + dateObj.tm_mday + "/" + dateObj.tm_mon + "/" + dateObj.tm_year);