Converting json results to a date

Question

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How to format a JSON date?

I have the following result from a $getJSON call from JavaScript. How do I convert the start property to a proper date in JavaScript?

[ {"id":1,"start":"/Date(1238540400000)/"}, {"id":2,"start":"/Date(1238626800000)/"} ]

Thanks!

"1238540400000" what's this? Milliseconds since the year 1970? — cwap, Aug 07 '09 at 10:49
You could use JSON++ instead of JSON. [JSON++](https://github.com/brillout/jpp) is the same than JSON but with support for JavaScript types such as `Date`. — brillout, Nov 14 '18 at 11:06

score 104 · Accepted Answer · edited Apr 13 '18 at 16:07

104

You need to extract the number from the string, and pass it into the Date constructor:

var x = [{
    "id": 1,
    "start": "\/Date(1238540400000)\/"
}, {
    "id": 2,
    "start": "\/Date(1238626800000)\/"
}];

var myDate = new Date(x[0].start.match(/\d+/)[0] * 1);

The parts are:

x[0].start                                - get the string from the JSON
x[0].start.match(/\d+/)[0]                - extract the numeric part
x[0].start.match(/\d+/)[0] * 1            - convert it to a numeric type
new Date(x[0].start.match(/\d+/)[0] * 1)) - Create a date object

edited Apr 13 '18 at 16:07

Narendra Jadhav

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answered Aug 07 '09 at 10:53

Greg

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Don't * 1 to convert a string to a number. Use parseInt(number, 10). Also, if you want a cool trick like * 1, just try +str to make it a number. – Eli Grey Aug 07 '09 at 17:34
@Greg I want a short date instead of "Thu Apr 26 2018 14:39:28 GMT+0700 (SE Asia Standard Time)" – anhtv13 Apr 26 '18 at 07:40

Rudy · Answer 2 · 2018-11-21T17:30:08.273

99

I use this:

function parseJsonDate(jsonDateString){
    return new Date(parseInt(jsonDateString.replace('/Date(', '')));
}

Update 2018:

This is an old question. Instead of still using this old non standard serialization format I would recommend to modify the server code to return better format for date. Either an ISO string containing time zone information, or only the milliseconds. If you use only the milliseconds for transport it should be UTC on server and client.

2018-07-31T11:56:48Z - ISO string can be parsed using new Date("2018-07-31T11:56:48Z") and obtained from a Date object using dateObject.toISOString()
1533038208000 - milliseconds since midnight January 1, 1970, UTC - can be parsed using new Date(1533038208000) and obtained from a Date object using dateObject.getTime()

edited Nov 21 '18 at 17:30

answered Jun 02 '11 at 11:14

Rudy

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This wouldn't account for the closing `')/'` – Lee Englestone Jan 31 '13 at 11:38
8

The parseInt function parses only until it founds legal characters for int, then it stops. The closing `')/'` will not be parsed. – Rudy Feb 01 '13 at 09:19
Cool, but that doesn't sound very robust:P – Michiel Cornille Jul 09 '13 at 11:26
14

It is robust, in that it works every time, in all situations – J.T. Taylor Oct 31 '13 at 20:45
@J.T.Taylor /Date(1545442200000+0100)/ ? – Guillaume Beauvois Nov 19 '18 at 11:05
@GuillaumeBeauvois fair point, I suppose if you are expecting a JSON date string from .NET DataContractJsonSerializer for example. The OP showed a format that did not include the offset, and this solution would work for any and all dates returned in that format. – J.T. Taylor Nov 20 '18 at 20:05
1

@J.T.Taylor Yes indeed, I just wanted to mitigate your affirmation : "it works every time, in all situations" – Guillaume Beauvois Nov 21 '18 at 08:06

score 11 · Answer 3 · answered Dec 27 '10 at 16:11

If you use jQuery

In case you use jQuery on the client side, you may be interested in this blog post that provides code how to globally extend jQuery's $.parseJSON() function to automatically convert dates for you.

You don't have to change existing code in case of adding this code. It doesn't affect existing calls to $.parseJSON(), but if you start using $.parseJSON(data, true), dates in data string will be automatically converted to Javascript dates.

It supports Asp.net date strings: /Date(2934612301)/ as well as ISO strings 2010-01-01T12_34_56-789Z. The first one is most common for most used back-end web platform, the second one is used by native browser JSON support (as well as other JSON client side libraries like json2.js).

Anyway. Head over to blog post to get the code. http://erraticdev.blogspot.com/2010/12/converting-dates-in-json-strings-using.html

thanks for the blog... I think you need to add "Z?" to the regex for matching the date otherwise we fail to match non-UTC dates. — Zephyr was a Friend of Mine, Apr 02 '12 at 15:34

Andreas Grech · Answer 4 · 2009-08-07T11:00:05.900

8

If that number represents milliseconds, use the Date's constructor :

var myDate = new Date(1238540400000);

edited Aug 07 '09 at 11:00

answered Aug 07 '09 at 10:53

Andreas Grech

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Actually more like myDate = new DateTime(1970, 1, 1).AddMilliseconds(jsonDateVal); – brenth Aug 14 '15 at 15:32

Converting json results to a date

4 Answers4

If you use jQuery

Linked