According to the specification for Intl.DateTimeFormat.prototype.resolvedOptions() (https://tc39.es/ecma402/#sec-intl.datetimeformat.prototype.resolvedoptions) step 5.d, none of the properties in Table 4 (weekday, era, year, month, day, dayPeriod, hour, minute, second, fractionalSecondDigits, timeZoneName) should be present on the returned object if dateStyle or timeStyle are present. JavaScriptCore currently does not implement this step correctly: > new Intl.DateTimeFormat('en', {dateStyle:'short'}).resolvedOptions().year "2-digit" This means you currently cannot always pass the object returned from resolvedOptions() back into the DateTimeFormat constructor as the options argument, for one thing.
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<rdar://problem/83782481>
Created attachment 439973 [details] Patch
Comment on attachment 439973 [details] Patch r=me, but we should make sure this gets captured in test262.
Committed r283460 (242439@main): <https://commits.webkit.org/242439@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 439973 [details].