Weird behavior with daylight saving rule

[andywu0408]

var a = moment.tz('2018-10-05', 'America/Los_Angeles').format('z');
var b = moment.tz('2028-10-05', 'America/Los_Angeles').format('z');

console.log(a+", "+b) // should output "PDT, PDT". But my program outputs "PDT, PST", which is wrong. Why??

Both "a" and "b" should be "PDT", since both times are during daylight savings.

However, my program always output "PST" for b, does anyone happens to know why?

I'm using the newest versions:

1. moment-timezone: "0.5.31"
2. moment: "2.29.1"

[andywu0408]

Could this be possibly related to Issue#798, Issue#881? I noticed that the wrong conversion of timezone abbreviation & offset only happens in a far future date like 2028 in my example (b).

[andywu0408]

Solution: Changing data file to "moment-timezone-with-data.js" fixed the issue. Please refer to moment timezone's documentation.

I was using the data file "moment-timezone-with-data-10-year-range", which only supported years from 2012-2022. Thus, the year 2028 was not covered.