timezone spoof for date.parse throws NaN

[Thorin-Oakenpants]

STR

• chameleon: spoof timezone: e.g. US Pacific
• https://arkenfox.github.io/TZP/tzp.html#region

https://github.com/arkenfox/TZP/blob/43c20737b4aeeeef4f2b119c89087a2223c7485e/js/region.js#L873-L901

[sereneblue]

Thanks for reporting @Thorin-Oakenpants.

It seems this is caused when a date pre-modern timezones is used. I have to do some further review to see what's the best way to handle those dates.

[Thorin-Oakenpants]

there's a lot more going on - e.g. even when not specifying spoof language, you modify the resolved locale for Intl.DateTimeFormat to en-US - at odds with all the rest (if you are not en-US of course)

IANAE on your code or webextensions, but you can simply pass undefined as the locale and timezone as the timeZone - for all the Intl and for toLocaleString and toLocaleDateString

edit: and when spoofing as e.g. Russian, nothing changes with navigator.language(s) to match, and locales are left alone: I'm not sure what your strategy is here, it's all so paradoxical :)

[khodedawsh]

I've noticed some problems with timezone, it causes problems with some websites, i can guess it's the same issue as the one mentioned here.

[Thorin-Oakenpants]

• timezone mismatches in Temporal so we get mixed
  • I'm spoofing as America/Winnipeg and my OS timezone is Pacific/Auckland
• timezone offset (it's getting your current offset using lastModified strings and some dates)
  • my real time is 2025-02-16 16-10-48
  • date is "tampered" with showing winnipeg time correct at 2025-02-15 21-10-48
  • control date is "tampered" with and IDK what on earth that is supposed to represent
    • if not tampered with it shows winnipeg time
  • the rest all show auckland time
  • EXSLT time offset is taken as the real value when we have mixed results
• timezone offsets (this is a history of offsets)
  • date.parse throws an error, as already mentioned
  • getTimezoneOffet is tampered with
  • the rest are not, which creates a mixed result

issues man ... you have issues :) anyway .. just thought I would alert to Temporal and all that is coming your way 😁