Luxon vs DayJS converting to UTC when in DST - date

Question

I'm wondering which library is doing this correctly. I think it is Luxon because it outputs what I want, but now I am not sure which is correct. Basically March 17 will be in DST. I establish a time in UTC, I change the timezone to PST, then I convert back. Luxon produces 8am UTC which is 9am with DST, but Dayjs produces 7am UTC which is 8am with DST.
const dj1 = dayjs("2022-03-17T16:00:00Z");
const djtz1 = dj1.tz("America/Los_Angeles");
const lux1 = DateTime.fromJSDate(d).setZone("America/Los_Angeles");
console.log(djtz1.utc().format());
console.log(lux1.setZone("utc").toISO());
The output of the above code is
DayJS
2022-03-17T15:00:00Z
Luxon
2022-03-17T16:00:00.000Z
https://codesandbox.io/s/luxon-playground-forked-k6rfcl?file=/src/index.js

Answer 1

Are you sure that you correctly configured timezone support in Day.js? They produce the same results:
<script src="https://unpkg.com/dayjs#1.11.0/plugin/utc.js"></script>
<script src="https://unpkg.com/dayjs#1.11.0/plugin/timezone.js"></script>
<script src="https://unpkg.com/dayjs#1.11.0/dayjs.min.js"></script>
<script type="module">
import {DateTime} from 'https://unpkg.com/luxon#2.3.1/src/luxon.js';
const {dayjs} = window;
dayjs.extend(window.dayjs_plugin_utc);
dayjs.extend(window.dayjs_plugin_timezone);
const isoString = '2022-03-17T16:00:00Z';
const dj1 = dayjs(isoString);
const djtz1 = dj1.tz('America/Los_Angeles');
const lux1 = DateTime.fromISO(isoString).setZone('America/Los_Angeles');
console.log({dayjs: djtz1.utc().format()});
console.log({luxon: lux1.setZone('utc').toISO()});
</script>