895737 - DateTimeFormat doesn't track current time zone

Status: RESOLVED DUPLICATE of bug 1348916

(Core :: JavaScript Engine, defect)

Description

[Norbert Lindenberg]

According to ECMA-402, section 6.4, Intl.DateTimeFormat uses the host environment’s current time zone if no time zone is provided to the constructor. Bug 796523 enabled the implementation of Date objects to track the operating system's time zone, but DateTimeFormat doesn't do that yet. As a result, toString and toLocaleString (with no time zone specified) can produce output reflecting different time zones at the same time. This can be observed, for example, with the test case at
http://norbertlindenberg.com/ecmascript/DateTest.html
See also
https://mail.mozilla.org/pipermail/es-discuss/2013-July/032087.html

Comment 1

[Philipp Kewisch [:Fallen] [:📆][:🧩]]

Would fixing this bug also provide the current OS timezone via Intl.DateTimeFormat().resolvedOptions().timeZone ? Also a related side question, is there an event of some sort when the system timezone changes?

Comment 2

[Zibi Braniecki [:zbraniecki][:gandalf]]

Andre, this also seems fixed now, am I correct?

Comment 3

[André Bargull [:anba]]

IIRC the DateTest.html page (before it went 404) also tested the behaviour when the time zone is manually changed during the life time of a web page. We still don't have that part correctly implemented (bug 1343826), so we probably should keep this bug open.

Comment 4

[André Bargull [:anba]]

All time zone computations are now handled through ICU, so we can close this particular bug. Missing time zone updates when the host time zone changes is already tracked in bug 1348916 (among others).