why I can't create a new Date() from given string? - javascript

I'm using moment.js to find a time in different timestamp.
I wrote a simple javascript:
$(function () {
var timestamp = 1443556318; //GMT Tue, 29 Sep 2015 19:51:58 GMT
var today2 = moment.unix(timestamp).tz('America/New_York').toString();
today = new Date(today2);
alert(today2);
alert(today);
var hh = today.getHours();
alert(hh); //why it shows me 21 instead of 15?
});
and seems like this line today = new Date(today2); does not work properly.
Can you help me with that?
http://jsfiddle.net/b8o5cvdz/3

It doesn't work because, you use the following constructor
new Date(dateString);
where the
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).
If you want to all the possible constructors, please have a look here.

Related

Javascript Date.UTC() vs moment.utc()

I'm looking for replacing moment js functionality with plain Javascript - the project I need to re-work is not going to have moment.js available going forward. I have not worked with javascript Date in a while, so needs some good eyes on this. My question is two-fold.
Part 1: what I get with Date.UTC() is not the same as the value I get with moment.utc()
//original value: Mon Mar 04 2019 05:21:00 GMT-0800 (Pacific Standard Time)
var m = moment(date);
m.utc();
return m.format('YYYY-MM-DD[T]HH:mm:ss[Z]');
//m.format: 2019-03-04T13:21:00Z
This is my replacement for m.utc (it designers improvement):
var d = new Date(date);
var utcVal = Date.UTC(d.getFullYear(), d.getMonth(), d.getDate(), d.getHours(), d.getMinutes(), d.getSeconds(), d.getMilliseconds());
var d2 = new Date(utcVal);
var sec = d2.getSeconds()<10? "0"+d2.getSeconds():d2.getSeconds();
var mm = d2.getMonth()<10? "0"+(d2.getMonth()+1):d2.getMonth();
var formated = d2.getFullYear()+"-"+mm+"-"+d2.getDate()+"T"+d2.getHours()+":"+d2.getMinutes()+":"+sec+"Z";
//d2 formated: 2019-03-3T21:21:00Z
I'd like to have something much cleaner than what I have above. Most glaring problem is that both the date and the hours are wrong. How can I fix this without usage of any other external libraries?
Part 2: I would like to confirm if what I already have for moment replacement is the right thing:
//value: 2019-03-04T13:21:00Z
var m = moment.utc(value);
m.local();
return m.toDate();
Here is my replacement for the above (it seems the .utc conversion is not used, .local is used instead):
var d = new Date(value);
return new Date(d.toLocaleString());
The above appears to be doing the right thing, but I wonder if there are edge cases I'm not thinking of.
For Part 1, you should look into the toISOString() method. Attach that to the Date object and it will return a string in the format you're looking for with a lot less work.
I could be misunderstanding, but seems as though toISOString would satisfy the requirement here:
var event = new Date('Mon Mar 04 2019 05:21:00 GMT-0800');
console.log(event.toString());
console.log(event.toISOString());

Date returns NaN in IE [duplicate]

Why cannot IE parse this string as a Date object.
var d = Date.parse("Fri Jun 11 04:55:12 +0000 2010"); // returns NaN
However, it works well in FireFox. I am running IE 8.
Thanks.
You are getting NaN value in IE 8 and its working in Firefox because the format of the string varies with browser and operating system.
For example, in IE6 for Windows XP, the string is in the following format:
Tue Dec 05 16:47:20 CDT 2006
But in Firefox for Windows XP, the string is
Tue Dec 05 2006 16:47:20 GMT-0500
to make it compatible with both browser you will have to first check the browser in your
javascript code and then accordingly give your input date string.
I've found the jQuery Globalization Plugin date parsing to work best. Other methods had cross-browser issues and stuff like date.js had not been updated in quite a while.
You also don't need a datePicker on the page. You can just call something similar to the example given in the docs:
$.datepicker.parseDate('yy-mm-dd', '2007-01-26');
Is solved my problem by creating an date object and let me give it back the timestamp.
But for this you need to convert you string into this format:
year, month, date, hours, minutes, seconds,ms
an example would be like:
dateObj = new Date(year, month, date);
timestamp = dateObj.getTime();
This works save in IE and FF.
IE Dev Center: Date Object (JavaScript)
Mozilla Dev Network: Date
For your example you would to something like this:
//your string
var str = "Fri Jun 11 04:55:12 +0000 2010";
//maps months to integer from 0 to 11
var monthArray = {"Jan":0, "Feb":1, "Mar":2, "Apr":3, "May":4, "Jun":5, "Jul":6, "Aug":7, "Sep":8, "Oct":9, "Nev":10, "Dec":11};
//get the values from the string
var regex = /^[^ ]+ ([^ ]+) (\d{1,2}) (\d{2}):(\d{2}):(\d{2}) \+(\d{4}) (\d{4})$/;
match = regex.exec(str);
var month = monthArray[match[1]],
date = match[2],
hours = match[3],
minutes = match[4],
seconds = match[5],
ms = match[6],
year = match[7];
//create date object with values
var dateObject = new Date(year, month, date, hours, minutes , seconds, ms);
var ts = dateObject.getTime(); //timestamp in ms
Problem
In case your date is stored in SQL datetime like 2020-04-07 05:30:00 and want to parse it in IE. When you parse it with JavaScript in IE using new Date(), it outputs Invalid Date while latest versions of Chrome and Firefox parse this date correctly.
Solution
You have to replace <space> with T in datetime string coming from SQL.
Example
let myDate = '2020-04-07 05:30:00';
let myFormattedDate = myDate.replace(' ', 'T'); // '2020-04-07T05:30:00'
console.log(new Date(myFormattedDate));
because of the +00000. try to add that the last
var d = Date.parse("Fri Jun 11 04:55:12 2010 +0000");
This may help you. I just solved a problem similar to this.
Problem with Javascript Date function in IE 7, returns NaN

Convert UTC date format into javascript format

How can I convert a date from:
Thu, 1 July 2011 22:30:00 to '2011-07-01T13:51:50.417' using javascript.
I get the UTC format when I do a new date.
IE causes me issues when I first create a date object as it shows: NaN
You could generate a new Date-Object and then get the different parts:
var today = new Date();
var year = today.getFullYear(); // Returns 2012
var month = today.getMonth()+1; // Returns the month (zero-based)
...
Then you can create a new string like you need it.
possible duplicate try search next time
stackoverflow question
Try http://www.datejs.com/. It is a JavaScript Date Library with an extended Date.parse method and a Date.parseExact method, which lets you specify a format string. See DateJS APIDocumentation.
and then you can manipulate it as you want
The d3.js library has some very solid routines for date conversions. See https://github.com/mbostock/d3/wiki/Time-Formatting#wiki-parse.

Invalid date in safari

alert(new Date('2010-11-29'));
chrome, ff doesn't have problems with this, but safari cries "invalid date". Why ?
edit : ok, as per the comments below, I used string parsing and tried this :
alert(new Date('11-29-2010')); //doesn't work in safari
alert(new Date('29-11-2010')); //doesn't work in safari
alert(new Date('2010-29-11')); //doesn't work in safari
edit Mar 22 2018 : Seems like people are still landing here - Today, I would use moment or date-fns and be done with it. Date-fns is very much pain free and light as well.
For me implementing a new library just because Safari cannot do it correctly is too much and a regex is overkill.
Here is the oneliner:
console.log (new Date('2011-04-12'.replace(/-/g, "/")));
The pattern yyyy-MM-dd isn't an officially supported format for Date constructor. Firefox seems to support it, but don't count on other browsers doing the same.
Here are some supported strings:
MM-dd-yyyy
yyyy/MM/dd
MM/dd/yyyy
MMMM dd, yyyy
MMM dd, yyyy
DateJS seems like a good library for parsing non standard date formats.
Edit: just checked ECMA-262 standard. Quoting from section 15.9.1.15:
Date Time String Format
ECMAScript defines a string
interchange format for date-times
based upon a simplification of the ISO
8601 Extended Format. The format is
as follows: YYYY-MM-DDTHH:mm:ss.sssZ
Where the fields are as follows:
YYYY is the decimal digits of the year in the Gregorian calendar.
"-" (hyphon) appears literally twice in the string.
MM is the month of the year from 01 (January) to 12 (December).
DD is the day of the month from 01 to 31.
"T" appears literally in the string, to indicate the beginning of
the time element.
HH is the number of complete hours that have passed since midnight as two
decimal digits.
":" (colon) appears literally twice in the string.
mm is the number of complete minutes since the start of the hour as
two decimal digits.
ss is the number of complete seconds since the start of the minute
as two decimal digits.
"." (dot) appears literally in the string.
sss is the number of complete milliseconds since the start of the
second as three decimal digits. Both
the "." and the milliseconds field may
be omitted.
Z is the time zone offset specified as "Z" (for UTC) or either "+" or "-"
followed by a time expression hh:mm
This format includes date-only forms:
YYYY
YYYY-MM
YYYY-MM-DD
It also includes time-only forms with
an optional time zone offset appended:
THH:mm
THH:mm:ss
THH:mm:ss.sss
Also included are "date-times" which
may be any combination of the above.
So, it seems that YYYY-MM-DD is included in the standard, but for some reason, Safari doesn't support it.
Update: after looking at datejs documentation, using it, your problem should be solved using code like this:
var myDate1 = Date.parseExact("29-11-2010", "dd-MM-yyyy");
var myDate2 = Date.parseExact("11-29-2010", "MM-dd-yyyy");
var myDate3 = Date.parseExact("2010-11-29", "yyyy-MM-dd");
var myDate4 = Date.parseExact("2010-29-11", "yyyy-dd-MM");
I was facing a similar issue. Date.Parse("DATESTRING") was working on Chrome (Version 59.0.3071.115 ) but not of Safari (Version 10.1.1 (11603.2.5) )
Safari:
Date.parse("2017-01-22 11:57:00")
NaN
Chrome:
Date.parse("2017-01-22 11:57:00")
1485115020000
The solution that worked for me was replacing the space in the dateString with "T". ( example : dateString.replace(/ /g,"T") )
Safari:
Date.parse("2017-01-22T11:57:00")
1485086220000
Chrome:
Date.parse("2017-01-22T11:57:00")
1485115020000
Note that the response from Safari browser is 8hrs (28800000ms) less than the response seen in Chrome browser because Safari returned the response in local TZ (which is 8hrs behind UTC)
To get both the times in same TZ
Safari:
Date.parse("2017-01-22T11:57:00Z")
1485086220000
Chrome:
Date.parse("2017-01-22T11:57:00Z")
1485086220000
I use moment to solve the problem.
For example
var startDate = moment('2015-07-06 08:00', 'YYYY-MM-DD HH:mm').toDate();
To have a solution working on most browsers, you should create your date-object with this format
(year, month, date, hours, minutes, seconds, ms)
e.g.:
dateObj = new Date(2014, 6, 25); //UTC time / Months are mapped from 0 to 11
alert(dateObj.getTime()); //gives back timestamp in ms
works fine with IE, FF, Chrome and Safari. Even older versions.
IE Dev Center: Date Object (JavaScript)
Mozilla Dev Network: Date
convert string to Date fromat (you have to know server timezone)
new Date('2015-06-16 11:00:00'.replace(/\s+/g, 'T').concat('.000+08:00')).getTime()
where +08:00 = timeZone from server
I had the same issue.Then I used moment.Js.Problem has vanished.
When creating a moment from a string, we first check if the string
matches known ISO 8601 formats, then fall back to new Date(string) if
a known format is not found.
Warning: Browser support for parsing strings is inconsistent. Because
there is no specification on which formats should be supported, what
works in some browsers will not work in other browsers.
For consistent results parsing anything other than ISO 8601 strings,
you should use String + Format.
e.g.
var date= moment(String);
For people using date-fns we can parseISO date and use it to format
Invalid
import _format from 'date-fns/format';
export function formatDate(date: string, format: string): string {
return _format(new Date(date), format);
}
This function on safari throw error with Invalid date.
Solution
To fix it we should use:
import _format from 'date-fns/format';
import _parseISO from 'date-fns/parseISO';
export function formatDate(date: string, format: string): string {
return _format(_parseISO(date), format);
}
Though you might hope that browsers would support ISO 8601 (or date-only subsets thereof), this is not the case. All browsers that I know of (at least in the US/English locales I use) are able to parse the horrible US MM/DD/YYYY format.
If you already have the parts of the date, you might instead want to try using Date.UTC(). If you don't, but you must use the YYYY-MM-DD format, I suggest using a regular expression to parse the pieces you know and then pass them to Date.UTC().
How about hijack Date with fix-date? No dependencies, min + gzip = 280 B
I am also facing the same problem in Safari Browser
var date = new Date("2011-02-07");
console.log(date) // IE you get ‘NaN’ returned and in Safari you get ‘Invalid Date’
Here the solution:
var d = new Date(2011, 01, 07); // yyyy, mm-1, dd
var d = new Date(2011, 01, 07, 11, 05, 00); // yyyy, mm-1, dd, hh, mm, ss
var d = new Date("02/07/2011"); // "mm/dd/yyyy"
var d = new Date("02/07/2011 11:05:00"); // "mm/dd/yyyy hh:mm:ss"
var d = new Date(1297076700000); // milliseconds
var d = new Date("Mon Feb 07 2011 11:05:00 GMT"); // ""Day Mon dd yyyy hh:mm:ss GMT/UTC
Use the below format, it would work on all the browsers
var year = 2016;
var month = 02; // month varies from 0-11 (Jan-Dec)
var day = 23;
month = month<10?"0"+month:month; // to ensure YYYY-MM-DD format
day = day<10?"0"+day:day;
dateObj = new Date(year+"-"+month+"-"+day);
alert(dateObj);
//Your output would look like this "Wed Mar 23 2016 00:00:00 GMT+0530 (IST)"
//Note this would be in the current timezone in this case denoted by IST, to convert to UTC timezone you can include
alert(dateObj.toUTCSting);
//Your output now would like this "Tue, 22 Mar 2016 18:30:00 GMT"
Note that now the dateObj shows the time in GMT format, also note that the date and time have been changed correspondingly.
The "toUTCSting" function retrieves the corresponding time at the Greenwich meridian. This it accomplishes by establishing the time difference between your current timezone to the Greenwich Meridian timezone.
In the above case the time before conversion was 00:00 hours and minutes on the 23rd of March in the year 2016. And after conversion from GMT+0530 (IST) hours to GMT (it basically subtracts 5.30 hours from the given timestamp in this case) the time reflects 18.30 hours on the 22nd of March in the year 2016 (exactly 5.30 hours behind the first time).
Further to convert any date object to timestamp you can use
alert(dateObj.getTime());
//output would look something similar to this "1458671400000"
This would give you the unique timestamp of the time
Best way to do it is by using the following format:
new Date(year, month, day, hours, minutes, seconds, milliseconds)
var d = new Date(2018, 11, 24, 10, 33, 30, 0);
This is supported in all browsers and will not give you any issues.
Please note that the months are written from 0 to 11.
For me the issue was I forgot to add 0 before the single digit month or day in YYYY-MM-DD format.
What I was parsing: 2021-11-5
What it should be: 2021-11-05
So, I wrote a little utility which converts YYYY-M-D to YYYY-MM-DD i.e. 2021-1-1 to 2021-01-01:
const date = "2021-1-1"
const YYYY = date.split("-")[0];
//convert M->MM i.e. 2->02
const MM =
date.split("-")[1].length == 1
? "0" + date.split("-")[1]
: date.split("-")[1];
//convert D->DD i.e. 2->02
const DD =
date.split("-")[2].length == 1
? "0" + date.split("-")[2]
: date.split("-")[2];
// YYYY-MM-DD
const properDateString = `${YYYY + "-" + MM + "-" + DD}`;
const dateObj = new Date(properDateString);
As #nizantz previously mentioned, using Date.parse() wasn't working for me in Safari. After a bit of research, I learned that the lastDateModified property for the File object has been deprecated, and is no longer supported by Safari. Using the lastModified property of the File object resolved my issues. Sure dislike it when bad info is found online.
Thanks to all who contributed to this post that assisted me in going down the path I needed to learn about my issue. Had it not been for this info, I never would have probably figured out my root issue. Maybe this will help someone else in my similar situation.
Arriving late to the party but in our case we were getting this issue in Safari & iOS when using ES6 back tick instead of String() to type cast
This was giving 'invalid date' error
const dateString = '2011-11-18';
const dateObj = new Date(`${dateString}`);
But this works
const dateObj = new Date(String(dateString));
In my case, it wasn't the formatting, it was because in my backend Node.js Model, I was defining the database variable as a String instead of a Date.
My backend Node Database Model said:
starttime:{
type: String,
}
instead of the correct:
starttime:{
type: Date,
}
The same problem facing in Safari and it was solved by inserting this in web page
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=Intl.~locale.en"></script>
Hope it will work also your case too
Thanks
This will not work alert(new Date('2010-11-29')); safari have some weird/strict way of processing date format alert(new Date(String('2010-11-29'))); try like this.
(Or)
Using Moment js will solve the issue though, After ios 14 the safari gets even weird
Try this alert(moment(String("2015-12-31 00:00:00")));
Moment JS
use the format 'mm/dd/yyyy'. For example :- new Date('02/28/2015'). It works well in all browsers.
This is not the best solution, although I simply catch the error and send back current date. I personally feel like not solving Safari issues, if users want to use a sh*t non-standards compliant browser - they have to live with quirks.
function safeDate(dateString = "") {
let date = new Date();
try {
if (Date.parse(dateString)) {
date = new Date(Date.parse(dateString))
}
} catch (error) {
// do nothing.
}
return date;
}
I'd suggest having your backend send ISO dates.

Javascript convert "05/27 11:00pm" to date?

How does one convert a string of a date without a year to a JS Date object? And how does one convert a date string with a year and a time into a JS Date object?
Many different date formats can be converted to date objects just by passing them to the Date() constructor:
var date = new Date(datestring);
Your example date doesn't work for two reasons. First, it doesn't have a year. Second, there needs to be a space before "pm" (I'm not sure why).
// Wed May 27 2009 23:00:00 GMT-0700 (Pacific Daylight Time)
var date = new Date("2009/05/27 11:00 pm")
If the date formats you're receiving are consistent, you can fix them up this way:
var datestring = "05/27 11:00pm";
var date = new Date("2009/" + datestring.replace(/\B[ap]m/i, " $&"));
I'd use the Datejs library's parse method.
http://www.datejs.com/
I tried your example and it worked fine...
5/27 11:00pm
Wednesday, May 27, 2009 11:00:00 PM
I have used the Dojo time parser to do things like this:
Check it out:
http://api.dojotoolkit.org/jsdoc/HEAD/dojo.date.locale.parse
Not the cleanest, but works:
var strDate = '05/27 11:00pm';
var myDate = ConvertDate(strDate, '2009');
function ConvertDate(strWeirdDate, strYear)
{
strWeirdDate = strWeirdDate.replace(/ /, '/' + strYear + ' ');
return new Date(strWeirdDate);
}
Probably want to trim the string first as well.
Just another option, which I wrote:
DP_DateExtensions Library
It has a date/time parse method - pass in a mask and it'll validate the input and return a data object if they match.
Also supports date/time formatting, date math (add/subtract date parts), date compare, speciality date parsing, etc. It's liberally open sourced.

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