Validating Date with Regex

Question

I need a regex to pattern match the following -

mm/dd/yyyy

The following date entries should pass validation:

05/03/2012
5/03/2012
05/3/2012
5/3/2012

Also, after validating above regex, what is the best way convert above date string to Date object?

http://www.regular-expressions.info/dates.html simply adjust the order of the date components — Martin Ender, Oct 17 '12 at 11:31

Denys Séguret · Accepted Answer · 2012-10-17T11:59:36.373

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You should do the check and the parsing in one go, using split, parseInt and the Date constructor :

function toDate(s) {
  var t = s.split('/');
  try {
     if (t.length!=3) return null;
     var d = parseInt(t[1],10);
     var m = parseInt(t[0],10);
     var y = parseInt(t[2],10);
     if (d>0 && d<32 && m>0 && m<13) return new Date(y, m-1, d);
  } catch (e){}
}

var date = toDate(somestring);
if (date) // ok
else // not ok

DEMONSTRATION :

01/22/2012 ==> Sun Jan 22 2012 00:00:00 GMT+0100 (CET)
07/5/1972 ==> Wed Jul 05 1972 00:00:00 GMT+0100 (CEST)
999/99/1972 ==> invalid

As other answers of this page, this wouldn't choke for 31 in February. That's why for all serious purposes you should instead use a library like Datejs.

edited Oct 17 '12 at 11:59

answered Oct 17 '12 at 11:33

Denys Séguret

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Interesting solution but it will happily accept 99/99/99 as a valid date. The JavaScript Date function will produce a valid date form any any numeric values. You should validate them before calling date. – HBP Oct 17 '12 at 11:48
@HBP +1 You're right... I didn't think about that. I'll fix it. – Denys Séguret Oct 17 '12 at 11:49
@HBP But as other answers here, it's still happy with 02/31/2012. So I recommend to use a library like Datejs (or another but I use Datejs without problem). – Denys Séguret Oct 17 '12 at 11:55

score 0 · Answer 2 · edited May 23 '17 at 11:43

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This one should do it:

((?:[0]?[1-9]|[1][012])[-:\\/.](?:(?:[0-2]?\\d{1})|(?:[3][01]{1}))[-:\\/.](?:(?:[1]{1}\\d{1}\\d{1}\\d{1})|(?:[2]{1}\\d{3})))(?![\\d])

(It is taken from txt2re.com)

You should also take a look at this link.

edited May 23 '17 at 11:43

Community

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answered Oct 17 '12 at 11:32

oopbase

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score 0 · Answer 3 · edited May 23 '17 at 12:12

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"/^(0?[1-9]|[12][0-9]|3[01])[\/\-](0?[1-9]|1[012])[\/\-]\d{4}$/"

link: Javascript date regex DD/MM/YYYY

edited May 23 '17 at 12:12

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answered Oct 17 '12 at 11:36

Yogesh

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Paul S. · Answer 4 · 2012-10-17T11:48:19.367

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var dateStr = '01/01/1901',
    dateObj = null,
    dateReg = /^(?:0[1-9]|1[012]|[1-9])\/(?:[012][1-9]|3[01]|[1-9])\/(?:19|20)\d\d$/;
    //             01 to 12 or 1 to 9   /    01 to 31  or  1 to 9   /  1900 to 2099

if( dateStr.match( dateReg ) ){
    dateObj = new Date( dateStr ); // this will be in the local timezone
}

edited Oct 17 '12 at 11:48

answered Oct 17 '12 at 11:41

Paul S.

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Validating Date with Regex

4 Answers4