fromFormat and unix epoch

[nlooije]

Describe the bug
I cannot use the token 'x' and 'X' to convert a unix epoch time in (milli)seconds to a datetime using the .fromFormat() method.

To Reproduce
luxon.DateTime.fromFormat('1769758221', 'X')

Actual vs Expected behavior
fromFormat() method gives a unparseable error with explanation the input "1769758221" can't be parsed as format X .
I expect the result to be datetime object which when converted toISO() is 2026-01-30T08:30:21.000+01:00

Desktop:

• OS: Windows 11
• Browser Chrome 144.0.7559.97
• Luxon version 3.7.2
• Europe/Amsterdam

Additional context
I may be misunderstanding if fromFormat() method can convert from unix epoch timestamps at all. It is not clear from the documentation. There is a macro token 'x' and 'X' but it seems to work for the toFormat() method instead.

[diesieben07]

The tokens for fromFormat and toFormat are different (see the different tables for formatting and parsing). They align in many places, but not everything that can be formatted can also be parsed, due to ambiguities or lack of browser APIs. For example, you can format a time zone as a short string ("EST" for example), but the resulting string is ambiguous, so there is no parsing token for it.
"X" and "x" are formatting tokens, but not parsing tokens. It should be easy to add the parsing tokens, but I wouldn't take this as a high priority issue, because you can use fromMillis and fromSeconds.

[JacquesN16]

@diesieben07 From your explanation I think I have an idea how we could implement the "x" and "X" as parsing tokens in tokenParser.
Should I create a PR for this ?

[diesieben07]

@JacquesN16 Sure! If this is a feature you need or you just want to help out, feel free to send in a PR.