Wrong year calculation for ISO Dates before 1970

[johann-sonntagbauer]

When I try to parse ISO Dates before 1970 the year caluclation is wrong. It will add one year.

Which results in following very strange result:
moment('1970-01-01T00:00:00.000+01:00').isSame(moment('1969-01-01T00:00:00.000+01:00')) === true

used moment.version
"2.6.0"

[johann-sonntagbauer]

some additional details:

moment('1969-01-01T00:00:00.000+01:00').year()
1970

moment('1969-01-01T00:00:00.000').year()
1969
moment('1969-01-01T00:00:00.000+02:00').year()
1969

So the problem only exists when the timezone is the same as the actual browser timezone it seems.

[ichernev]

Are you on safari? Also what is your location (timezone, language).

[ichernev]

Ahh, you're right. This is happening because of a weird interplay between Date bug workaround (manually set the year if < 1970), and timezone and year shift because of it (because 1st jan 00:00 +1, is actually 31 Dec last year in local time).

I guess we need to rethink the way timezones are parsed. First parse, then verify, then apply offset.

[johann-sonntagbauer]

sounds reasonable 👍
Sorry but I can't give any advice here, tried to understand the logic a little but I gave up.

[ichernev]

The pr would fix it in next release dont worry. Thank you for reporting

[icambron]

Fixed by #1651. @ichernev writes the code, I close the tickets.