moment().format() incorrect on older browsers

[Unsfer]

Description of the Issue and Steps to Reproduce:
When converting to 'DD.MM.YYYY' format some rare dates becomes new, not equal to the initial

var date = "1983-04-01";
var ruDate = moment(date, 'YYYY-MM-DD').format('DD.MM.YYYY');
alert(date + " - " + ruDate);
// Output: "1983-04-01 - 31.03.1983"

http://jsfiddle.net/f3jus6cn/

Environment:
Reproduced this on Chromium 35 and Firefox 45.9.0
OS: Gentoo 2.2

Other information that may be helpful:

• The time zone setting: +0400
• The time and date at which the code was run: doesn't matter

[ashsearle]

Please can you run the code below and tell us the output:

var date = "1983-04-01";
var ruDate = moment(date, 'YYYY-MM-DD');
console.log(moment.version, moment.locale(), ruDate.toISOString(), ruDate.toDate().toString());

[Unsfer]

moment.version: "2.2.1"
moment.locale(): error moment.locale is not a function
toISOString: "1983-03-31T19:00:00.000Z"
toDate: "Thu Mar 31 1983 23:00:00 GMT+0400 (KUYT)"

[ashsearle]

moment 2.2.1 - from September 2013?

You should probably upgrade and see if the bug is fixed in a more recent version of moment.

[Unsfer]

Tried latest version:

moment.version: "2.22.2"
moment.locale(): "ru"
toISOString: "1983-03-31T19:00:00.000Z"
toDate: "Thu Mar 31 1983 23:00:00 GMT+0400 (KUYT)"

[ashsearle]

Interesting. Daylight savings time started at midnight beginning 1st April 1983, so clocks moved forward to 1AM.

moments represent a date and a time. 1983-04-01 is effectively shorthand for trying to create a moment at 00:00:00 in local time. But, that date + time doesn't exist in your locale.

This sounds very similar to a Brazil DST issue, so this might be fixed if PR #4338 gets merged.

[marwahaha]

I think this is working now (2.24.0).

Please re-open if you still have issues.