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When converting date, I get previous day

I want to convert a string into a date "as it is".
const date = "8/16/2019"
console.log(new Date(date))
However, I get:
As you can see I get the prevous day. I was thinking that it might be a timezone issue, even though there is no timezone that I am converting it from.
Any suggestions how to convert is as it is?
I appreciate you replies!

If your format is consistent, you could split on / and use Date.UTC. Creating your new Date from that would ensure it's UTC.
const date = "8/16/2019"
const [month,day,year] = date.split("/");
const utcDate = Date.UTC(year,month-1,day);
console.log(new Date(utcDate));

const date = "8/16/2019"
console.log(new Date(date).toLocaleString("en-US", {timeZone: "Asia/kolkata"}))
Note:- You need to add timezone

You can use toLocaleDateString
console.log(new Date("8/16/2019").toLocaleDateString('en-us', {timeZone: "Asia/Kolkata"}))

new Date("8/16/2019") will create a date object using your current timezone. Add a "Z" at the end if you want your date to be in UTC.
console.log(new Date("8/16/2019Z"))
EDIT
It appears that Firefox is not implementing the parsing of standard date format. Unfortunately until recently how exactly was a date parsed was completeley based on heuristics and intrinsically non portable.
Looking at Firefox bug tracker seems the issue has been discussed but the problem is still present (some toolkit just works around by replacing "Z" with "+00:00" before calling the parser).
The only way to be sure on every browser is to parse the string yourself and build the date from the fields. I didn't notice because I'm using chrome instead (in both chrome and Node works as expected).
EDIT 2
After more investigation seems the standard requires that:
If you use yyyy-mm-ddThh:mm:ssz then you get what ISO format for datetime defines it to be. Also the syntax described in the standard is not very precise and for example is not clear to me if the time zone can be present when no time is present (Chrome says yes, Firefox says no).
If you use another format then anything goes (so for example there is no string that is guaranteed to issue an invalid date response).
In other words new Date("8/16/2019") is not portable Javascript (with the meaning that you don't know what date / time / timezone you will get, if any). Either you parse yourself the date or you just live with what that version of that Javascript engine in that moment decides to give you.

Generate specific date format in JavaScript

I have to generate date in specific format in javascript, The required format is "2017-12-07T14:47:00+0530". I have tried using moments but got stuck in time zone field.
moment().format('YYYY-MM-DDTHH:mm:ssZ'); //output 2018-03-06T14:32:45+05:30

Take a look at the docs
You want the ZZ timezone format rather than a single Z.
console.log(new moment().format('YYYY-MM-DDTHH:mm:ssZZ'))
// 2018-03-06T09:14:44+0000
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.20.1/moment.js"></script>

Moment.js 2 different date strings when i parse using moment gives same value

I am parsing 2 different date strings
var d1 = '2014-02-01T00:00:00.000+0530'
var d2 = '2014-02-23T00:00:00.000+0530'
when i parse them using moment
alert(moment(d1, 'YYYY-MM-dd"T"HH:mm:ss.fffffff"Z"').toDate());
alert(moment(d2, 'YYYY-MM-dd"T"HH:mm:ss.fffffff"Z"').toDate());
both of them print Sat Feb 1 2014 xxxxx
what is wrong with it??
here is the link to the fiddle i created
jsfiddle

I think your moment formatting string is causing you the problem. If I remove this, the dates do not print as the same.
http://jsfiddle.net/K5ub8/7/
EDIT: The specific issue is you are using dd for day, instead of DD. http://momentjs.com/docs/#/parsing/string-format/
Here is your fiddle fixed:
http://jsfiddle.net/K5ub8/9/
However, I am not 100% sure about the fractional seconds, I believe it is SSS instead of fffffff but I would test this if you need to cater for fractional seconds.
I should mention that if you are converting it back into a JavaScript date object anyway with toDate(), then you don't really need the moment formatting parameter as the date will be formatted in JSON Date format.
I would question why you would want to generate a moment formatted date, and then convert it back to JavaScript, a normal practice might be to receive a date in JavaScript format, then create a moment object which you can use to perform calculations and display in a nice user friendly way.

Simple answer: your format was off a bit.
http://jsfiddle.net/K5ub8/8/
After tweaking the format to be 'YYYY-MM-DDTHH:mm:ss.SSSZZ' rather than 'YYYY-MM-dd"T"HH:mm:ss.fffffff"Z"' it worked just fine. When you're trying to debug issues like this, it's always good to keep the format in a separate variable so you can use the same format that you're trying to parse out to display what you're getting. Had you done that, you would have noticed that 'YYYY-MM-dd"T"HH:mm:ss.fffffff"Z"' was messed up due to it printing out 2014-01-Fr"T"11:32:03.fffffff"-08:00". Which obviously isn't quite right.

How can I parse these strings into UTC dates?

I'm scraping a site, and the dates come in two forms:
11-22-2011 07:41 AM
Today # 07:41 AM
Both of these are GMT-8. I'd like to get a unix timestamp out of these, so that I can construct a meaningful date object
Any idea what timezone this might be? Around a month ago, the site was gibing GMT-9 times. Can javascript handle Daylight Saving Time automatically?
I'm having great difficultly parsing them. Part of the problem is the time zone.
At the moment, I'm using Date.js' parseExact:
date = Date.parseExact(date + ' PDT', 'MM-dd-yyyy H:mm tt zzz');
Hovever, this seems to get parse 12AM as 12:00, not 0:00. Additionally, I'm at a total loss as to how to handle the ones starting with today #.

When I try both of your examples using the interactive parser at http://www.datejs.com/ I get the expected results.
The timezone in question is likely "US West Coast", aka "Pacific Time".
Unfortunately that means different things at different times of the year. In the spring and summer that timezone is called "PDT" (GMT-0700) and the rest of the time it's called "PST" (GMT-0800).
To further complicate matters the dates on which that changes aren't the same as the dates on which other zones (e.g. in Europe) change.
I don't think there's a way of specifying a timezone value to Date.js that can take that into account automatically.

You could write your own, timezone-aware date parsing logic which takes into account the timezone of the remote server.
pseudo-code:
if date starts with "Today #"
replace "Today #" with currentDateInRemoteTimezone in date
endif
parse_timezone-aware(date)

Why not just add HHHH:mm zzz to get 12:00?

Use a lowercase h for the hour to get 1-12. The uppercase H gives 0-23. From your examples I would use a format of
MM-dd-yyyy hh:mm tt
Documentation
You should handle "Today # " separately. When you find that string, expect the next token to be a time in the form hh:mm tt. Parse the second part as a time and combine it with today's (local) date. That is not hard to do programmatically with Date.js functions, but you won't find a single format string that captures the "Today #" part (as you know).

How to change the date format in JavaScript?

I am using one jquery date picker,
with using picker i am getting date in like this format
Friday, May 21, 2010
Now i want to add one day in this date so i think, i can only do if i change the date in exact format like
21/5/2010
I want to only convert that bcz i want to add one day to the particular date.
So what do u suggest me? How can I do that?
Can i do without converting it ?
thanks in advance....

Take a look at http://docs.jquery.com/UI/Datepicker#option-dateFormat

datejs may be useful to you.

In addition to the formatting options given by others, you should add using date objects rather than to the string representation of the date object.
I.E.
// add 5 days to today
var myDate=new Date();
myDate.setDate(myDate.getDate()+5);

I think you need to detail what jQuery plugin do you use.
Is it this one? http://jqueryui.com/demos/datepicker/
If so, then when you cann getDate method, you'll get Date object representing a date. You can easily manipulate it.

The date format has nothing to do with how dates are stored; it only affects the way dates are displayed. JavaScript has a native Date object and jQuery UI's Datepicker allows to access such object:
http://jqueryui.com/demos/datepicker/#method-getDate
Once you have a Date object, you can alter it to suit your needs:
https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Date
Finally, you can feed it back into Datepicker:
http://jqueryui.com/demos/datepicker/#method-setDate