+00:00 timezone bug

[janousek]

This line is causing several bugs when working with +00:00 timezones (for example Europe/Lisbon):

dayjs/src/plugin/utc/index.js

Line 117 in b5a1391

? this.$offset + (this.$x.$localOffset || (new Date()).getTimezoneOffset()) : 0

It is because $localOffset is 0 (this is correct offset) and therefore value of (new Date()).getTimezoneOffset() is used (instead of the value 0).
Operator || cannot be used here, because it does not work correctly with $localOffset == 0.
This line should be changed into:

? this.$offset + (this.$x.$localOffset === null || this.$x.$localOffset === undefined ? (new Date()).getTimezoneOffset()) : 0

[DimaBur]

Have the same problem, created PR with fix #1678