Two issues:
- The intended range was 9 characters starting from index 1. Since the
second argument to String::substring() is the length, 10 is
potentially reading further than the string's length (when only
providing one fraction digit), causing an assertion failure crash.
- The spec's intention to skip the decimal separator by starting at
index 1 is incorrect, no decimal separator is present in the result of
parsing TimeZoneUTCOffsetFractionalPart. I filed a spec fix for this,
see: https://github.com/tc39/proposal-temporal/pull/1999
As all variables and numeric literals in the expression have an integral
data type, it would evaluate to an int and could easily overflow as
we're multiplying seconds with 10^9.
Introduce a floating point literal into the expression to make it result
in a double.
We can now recognize & normalize all time zones from the IANA time zone
database and not just 'UTC', which makes the LibJS Temporal
implementation a lot more useful! Thanks to the newly added LibTimeZone,
this was incredibly easy to implement :^)
This already includes these recent editorial changes in the Temporal
spec: 27bffe1
