NodaTime IANA 时区偏移量与 Moment JS 不匹配

Question

I recently started using NodaTime and I must say it is a fantastic piece of work.

However, just to test that I am doing things right, I took IANA timezone names from here and printed UTC Offsets for each using NodaTime.

/* string[] ALL_ZONE_NAMES = list of zone names */
foreach(var timezone in ALL_ZONE_NAMES)
        {
            var ob = DateTimeZoneProviders.Tzdb[timezone];
            Console.WriteLine($"{timezone} --> {ob.GetUtcOffset(new Instant())}");
        }

Now, for a particular timezone say Pacific/Apia , offset was printed as -11 ,

but when I tried same on Chrome browser (console) from the momentJS, I got +14

moment.tz(new Date().toISOString(), "Pacific/Apia").format()
"2020-12-10T01:33:13+14:00"

Am I missing something?

Answer 1

In the Noda Time code, you're using new Instant() , which refers to the Unix epoch (1970-01-01T00:00:00Z). In the Javascript code you're using new Date() which uses the current date and time.

Change your Noda Time code to use ob.GetUtcOffset(SystemClock.Instance.GetCurrentInstant()) to make it behave like the Javascript code.

Note that you can get a full list of transitions with offsets for all time zones in terms of Noda Time results at https://nodatime.org/tzvalidate/generate - and you can specify a zone and/or IANA database version as well, eg https://nodatime.org/tzvalidate/generate?version=2020d&zone=Pacific/Apia to just show the Pacific/Apia results using the 2020d database.