DateTimeFormatConstructor.cpp 22 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480
  1. /*
  2. * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
  3. *
  4. * SPDX-License-Identifier: BSD-2-Clause
  5. */
  6. #include <LibJS/Runtime/AbstractOperations.h>
  7. #include <LibJS/Runtime/Array.h>
  8. #include <LibJS/Runtime/Date.h>
  9. #include <LibJS/Runtime/GlobalObject.h>
  10. #include <LibJS/Runtime/Intl/AbstractOperations.h>
  11. #include <LibJS/Runtime/Intl/DateTimeFormat.h>
  12. #include <LibJS/Runtime/Intl/DateTimeFormatConstructor.h>
  13. #include <LibJS/Runtime/Temporal/TimeZone.h>
  14. #include <LibLocale/DateTimeFormat.h>
  15. #include <LibLocale/Locale.h>
  16. namespace JS::Intl {
  17. JS_DEFINE_ALLOCATOR(DateTimeFormatConstructor);
  18. // 11.1 The Intl.DateTimeFormat Constructor, https://tc39.es/ecma402/#sec-intl-datetimeformat-constructor
  19. DateTimeFormatConstructor::DateTimeFormatConstructor(Realm& realm)
  20. : NativeFunction(realm.vm().names.DateTimeFormat.as_string(), realm.intrinsics().function_prototype())
  21. {
  22. }
  23. void DateTimeFormatConstructor::initialize(Realm& realm)
  24. {
  25. Base::initialize(realm);
  26. auto& vm = this->vm();
  27. // 11.2.1 Intl.DateTimeFormat.prototype, https://tc39.es/ecma402/#sec-intl.datetimeformat.prototype
  28. define_direct_property(vm.names.prototype, realm.intrinsics().intl_date_time_format_prototype(), 0);
  29. u8 attr = Attribute::Writable | Attribute::Configurable;
  30. define_native_function(realm, vm.names.supportedLocalesOf, supported_locales_of, 1, attr);
  31. define_direct_property(vm.names.length, Value(0), Attribute::Configurable);
  32. }
  33. // 11.1.1 Intl.DateTimeFormat ( [ locales [ , options ] ] ), https://tc39.es/ecma402/#sec-intl.datetimeformat
  34. ThrowCompletionOr<Value> DateTimeFormatConstructor::call()
  35. {
  36. // 1. If NewTarget is undefined, let newTarget be the active function object, else let newTarget be NewTarget.
  37. return TRY(construct(*this));
  38. }
  39. // 11.1.1 Intl.DateTimeFormat ( [ locales [ , options ] ] ), https://tc39.es/ecma402/#sec-intl.datetimeformat
  40. ThrowCompletionOr<NonnullGCPtr<Object>> DateTimeFormatConstructor::construct(FunctionObject& new_target)
  41. {
  42. auto& vm = this->vm();
  43. auto locales = vm.argument(0);
  44. auto options = vm.argument(1);
  45. // 2. Let dateTimeFormat be ? CreateDateTimeFormat(newTarget, locales, options, any, date).
  46. auto date_time_format = TRY(create_date_time_format(vm, new_target, locales, options, OptionRequired::Any, OptionDefaults::Date));
  47. // 3. If the implementation supports the normative optional constructor mode of 4.3 Note 1, then
  48. // a. Let this be the this value.
  49. // b. Return ? ChainDateTimeFormat(dateTimeFormat, NewTarget, this).
  50. // 4. Return dateTimeFormat.
  51. return date_time_format;
  52. }
  53. // 11.2.2 Intl.DateTimeFormat.supportedLocalesOf ( locales [ , options ] ), https://tc39.es/ecma402/#sec-intl.datetimeformat.supportedlocalesof
  54. JS_DEFINE_NATIVE_FUNCTION(DateTimeFormatConstructor::supported_locales_of)
  55. {
  56. auto locales = vm.argument(0);
  57. auto options = vm.argument(1);
  58. // 1. Let availableLocales be %DateTimeFormat%.[[AvailableLocales]].
  59. // 2. Let requestedLocales be ? CanonicalizeLocaleList(locales).
  60. auto requested_locales = TRY(canonicalize_locale_list(vm, locales));
  61. // 3. Return ? SupportedLocales(availableLocales, requestedLocales, options).
  62. return TRY(supported_locales(vm, requested_locales, options));
  63. }
  64. // 11.1.2 CreateDateTimeFormat ( newTarget, locales, options, required, defaults ), https://tc39.es/ecma402/#sec-createdatetimeformat
  65. ThrowCompletionOr<NonnullGCPtr<DateTimeFormat>> create_date_time_format(VM& vm, FunctionObject& new_target, Value locales_value, Value options_value, OptionRequired required, OptionDefaults defaults)
  66. {
  67. // 1. Let dateTimeFormat be ? OrdinaryCreateFromConstructor(newTarget, "%DateTimeFormat.prototype%", « [[InitializedDateTimeFormat]], [[Locale]], [[Calendar]], [[NumberingSystem]], [[TimeZone]], [[Weekday]], [[Era]], [[Year]], [[Month]], [[Day]], [[DayPeriod]], [[Hour]], [[Minute]], [[Second]], [[FractionalSecondDigits]], [[TimeZoneName]], [[HourCycle]], [[DateStyle]], [[TimeStyle]], [[Pattern]], [[RangePatterns]], [[BoundFormat]] »).
  68. auto date_time_format = TRY(ordinary_create_from_constructor<DateTimeFormat>(vm, new_target, &Intrinsics::intl_date_time_format_prototype));
  69. // 2. Let requestedLocales be ? CanonicalizeLocaleList(locales).
  70. auto requested_locales = TRY(canonicalize_locale_list(vm, locales_value));
  71. // 3. Set options to ? CoerceOptionsToObject(options).
  72. auto* options = TRY(coerce_options_to_object(vm, options_value));
  73. // 4. Let opt be a new Record.
  74. LocaleOptions opt {};
  75. // 5. Let matcher be ? GetOption(options, "localeMatcher", string, « "lookup", "best fit" », "best fit").
  76. auto matcher = TRY(get_option(vm, *options, vm.names.localeMatcher, OptionType::String, AK::Array { "lookup"sv, "best fit"sv }, "best fit"sv));
  77. // 6. Set opt.[[localeMatcher]] to matcher.
  78. opt.locale_matcher = matcher;
  79. // 7. Let calendar be ? GetOption(options, "calendar", string, empty, undefined).
  80. auto calendar = TRY(get_option(vm, *options, vm.names.calendar, OptionType::String, {}, Empty {}));
  81. // 8. If calendar is not undefined, then
  82. if (!calendar.is_undefined()) {
  83. // a. If calendar cannot be matched by the type Unicode locale nonterminal, throw a RangeError exception.
  84. if (!::Locale::is_type_identifier(calendar.as_string().utf8_string_view()))
  85. return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, calendar, "calendar"sv);
  86. // 9. Set opt.[[ca]] to calendar.
  87. opt.ca = calendar.as_string().utf8_string();
  88. }
  89. // 10. Let numberingSystem be ? GetOption(options, "numberingSystem", string, empty, undefined).
  90. auto numbering_system = TRY(get_option(vm, *options, vm.names.numberingSystem, OptionType::String, {}, Empty {}));
  91. // 11. If numberingSystem is not undefined, then
  92. if (!numbering_system.is_undefined()) {
  93. // a. If numberingSystem cannot be matched by the type Unicode locale nonterminal, throw a RangeError exception.
  94. if (!::Locale::is_type_identifier(numbering_system.as_string().utf8_string_view()))
  95. return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, numbering_system, "numberingSystem"sv);
  96. // 12. Set opt.[[nu]] to numberingSystem.
  97. opt.nu = numbering_system.as_string().utf8_string();
  98. }
  99. // 13. Let hour12 be ? GetOption(options, "hour12", boolean, empty, undefined).
  100. auto hour12 = TRY(get_option(vm, *options, vm.names.hour12, OptionType::Boolean, {}, Empty {}));
  101. // 14. Let hourCycle be ? GetOption(options, "hourCycle", string, « "h11", "h12", "h23", "h24" », undefined).
  102. auto hour_cycle = TRY(get_option(vm, *options, vm.names.hourCycle, OptionType::String, AK::Array { "h11"sv, "h12"sv, "h23"sv, "h24"sv }, Empty {}));
  103. // 15. If hour12 is not undefined, then
  104. if (!hour12.is_undefined()) {
  105. // a. Set hourCycle to null.
  106. hour_cycle = js_null();
  107. }
  108. // 16. Set opt.[[hc]] to hourCycle.
  109. if (!hour_cycle.is_nullish())
  110. opt.hc = hour_cycle.as_string().utf8_string();
  111. // 17. Let localeData be %DateTimeFormat%.[[LocaleData]].
  112. // 18. Let r be ResolveLocale(%DateTimeFormat%.[[AvailableLocales]], requestedLocales, opt, %DateTimeFormat%.[[RelevantExtensionKeys]], localeData).
  113. auto result = resolve_locale(requested_locales, opt, DateTimeFormat::relevant_extension_keys());
  114. // 19. Set dateTimeFormat.[[Locale]] to r.[[locale]].
  115. date_time_format->set_locale(move(result.locale));
  116. // 20. Let resolvedCalendar be r.[[ca]].
  117. // 21. Set dateTimeFormat.[[Calendar]] to resolvedCalendar.
  118. if (result.ca.has_value())
  119. date_time_format->set_calendar(result.ca.release_value());
  120. // 22. Set dateTimeFormat.[[NumberingSystem]] to r.[[nu]].
  121. if (result.nu.has_value())
  122. date_time_format->set_numbering_system(result.nu.release_value());
  123. // 23. Let dataLocale be r.[[dataLocale]].
  124. auto data_locale = move(result.data_locale);
  125. // Non-standard, the data locale is needed for LibUnicode lookups while formatting.
  126. date_time_format->set_data_locale(data_locale);
  127. // 24. Let dataLocaleData be localeData.[[<dataLocale>]].
  128. Optional<::Locale::HourCycle> hour_cycle_value;
  129. Optional<bool> hour12_value;
  130. // 25. If hour12 is true, then
  131. // a. Let hc be dataLocaleData.[[hourCycle12]].
  132. // 26. Else if hour12 is false, then
  133. // a. Let hc be dataLocaleData.[[hourCycle24]].
  134. if (hour12.is_boolean()) {
  135. // NOTE: We let LibLocale figure out the appropriate hour cycle.
  136. hour12_value = hour12.as_bool();
  137. }
  138. // 27. Else,
  139. else {
  140. // a. Assert: hour12 is undefined.
  141. VERIFY(hour12.is_undefined());
  142. // b. Let hc be r.[[hc]].
  143. if (result.hc.has_value())
  144. hour_cycle_value = ::Locale::hour_cycle_from_string(*result.hc);
  145. // c. If hc is null, set hc to dataLocaleData.[[hourCycle]].
  146. if (!hour_cycle_value.has_value())
  147. hour_cycle_value = ::Locale::default_hour_cycle(data_locale);
  148. }
  149. // 28. Set dateTimeFormat.[[HourCycle]] to hc.
  150. date_time_format->hour_cycle = hour_cycle_value;
  151. // 29. Let timeZone be ? Get(options, "timeZone").
  152. auto time_zone_value = TRY(options->get(vm.names.timeZone));
  153. String time_zone;
  154. // 30. If timeZone is undefined, then
  155. if (time_zone_value.is_undefined()) {
  156. // a. Set timeZone to DefaultTimeZone().
  157. time_zone = MUST(String::from_utf8(system_time_zone_identifier()));
  158. }
  159. // 31. Else,
  160. else {
  161. // a. Set timeZone to ? ToString(timeZone).
  162. time_zone = TRY(time_zone_value.to_string(vm));
  163. }
  164. // 32. If IsTimeZoneOffsetString(timeZone) is true, then
  165. bool is_time_zone_offset_string = JS::is_time_zone_offset_string(time_zone);
  166. if (is_time_zone_offset_string) {
  167. // a. Let parseResult be ParseText(StringToCodePoints(timeZone), UTCOffset).
  168. auto parse_result = Temporal::parse_iso8601(Temporal::Production::TimeZoneNumericUTCOffset, time_zone);
  169. // b. Assert: parseResult is a Parse Node.
  170. VERIFY(parse_result.has_value());
  171. // c. If parseResult contains more than one MinuteSecond Parse Node, throw a RangeError exception.
  172. if (parse_result->time_zone_utc_offset_second.has_value())
  173. return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, time_zone, vm.names.timeZone);
  174. // d. Let offsetNanoseconds be ParseTimeZoneOffsetString(timeZone).
  175. auto offset_nanoseconds = parse_time_zone_offset_string(time_zone);
  176. // e. Let offsetMinutes be offsetNanoseconds / (6 × 10^10).
  177. auto offset_minutes = offset_nanoseconds / 60'000'000'000;
  178. // f. Assert: offsetMinutes is an integer.
  179. VERIFY(trunc(offset_minutes) == offset_minutes);
  180. // g. Set timeZone to FormatOffsetTimeZoneIdentifier(offsetMinutes).
  181. time_zone = format_offset_time_zone_identifier(offset_minutes);
  182. }
  183. // 33. Else if IsValidTimeZoneName(timeZone) is true, then
  184. else if (Temporal::is_available_time_zone_name(time_zone)) {
  185. // a. Set timeZone to CanonicalizeTimeZoneName(timeZone).
  186. time_zone = MUST(Temporal::canonicalize_time_zone_name(vm, time_zone));
  187. }
  188. // 34. Else,
  189. else {
  190. // a. Throw a RangeError exception.
  191. return vm.throw_completion<RangeError>(ErrorType::OptionIsNotValidValue, time_zone, vm.names.timeZone);
  192. }
  193. // 35. Set dateTimeFormat.[[TimeZone]] to timeZone.
  194. date_time_format->set_time_zone(time_zone);
  195. // NOTE: ICU requires time zone offset strings to be of the form "GMT+00:00"
  196. if (is_time_zone_offset_string)
  197. time_zone = MUST(String::formatted("GMT{}", time_zone));
  198. // 36. Let formatOptions be a new Record.
  199. ::Locale::CalendarPattern format_options {};
  200. // 37. Set formatOptions.[[hourCycle]] to hc.
  201. format_options.hour_cycle = hour_cycle_value;
  202. format_options.hour12 = hour12_value;
  203. // 38. Let hasExplicitFormatComponents be false.
  204. // NOTE: Instead of using a boolean, we track any explicitly provided component name for nicer exception messages.
  205. PropertyKey const* explicit_format_component = nullptr;
  206. // 39. For each row of Table 6, except the header row, in table order, do
  207. TRY(for_each_calendar_field(vm, format_options, [&](auto& option, PropertyKey const& property, auto const& values) -> ThrowCompletionOr<void> {
  208. using ValueType = typename RemoveReference<decltype(option)>::ValueType;
  209. // a. Let prop be the name given in the Property column of the row.
  210. // b. If prop is "fractionalSecondDigits", then
  211. if constexpr (IsIntegral<ValueType>) {
  212. // i. Let value be ? GetNumberOption(options, "fractionalSecondDigits", 1, 3, undefined).
  213. auto value = TRY(get_number_option(vm, *options, property, 1, 3, {}));
  214. // d. Set formatOptions.[[<prop>]] to value.
  215. if (value.has_value()) {
  216. option = static_cast<ValueType>(value.value());
  217. // e. If value is not undefined, then
  218. // i. Set hasExplicitFormatComponents to true.
  219. explicit_format_component = &property;
  220. }
  221. }
  222. // c. Else,
  223. else {
  224. // i. Let values be a List whose elements are the strings given in the Values column of the row.
  225. // ii. Let value be ? GetOption(options, prop, string, values, undefined).
  226. auto value = TRY(get_option(vm, *options, property, OptionType::String, values, Empty {}));
  227. // d. Set formatOptions.[[<prop>]] to value.
  228. if (!value.is_undefined()) {
  229. option = ::Locale::calendar_pattern_style_from_string(value.as_string().utf8_string_view());
  230. // e. If value is not undefined, then
  231. // i. Set hasExplicitFormatComponents to true.
  232. explicit_format_component = &property;
  233. }
  234. }
  235. return {};
  236. }));
  237. // 40. Let matcher be ? GetOption(options, "formatMatcher", string, « "basic", "best fit" », "best fit").
  238. matcher = TRY(get_option(vm, *options, vm.names.formatMatcher, OptionType::String, AK::Array { "basic"sv, "best fit"sv }, "best fit"sv));
  239. // 41. Let dateStyle be ? GetOption(options, "dateStyle", string, « "full", "long", "medium", "short" », undefined).
  240. auto date_style = TRY(get_option(vm, *options, vm.names.dateStyle, OptionType::String, AK::Array { "full"sv, "long"sv, "medium"sv, "short"sv }, Empty {}));
  241. // 42. Set dateTimeFormat.[[DateStyle]] to dateStyle.
  242. if (!date_style.is_undefined())
  243. date_time_format->set_date_style(date_style.as_string().utf8_string_view());
  244. // 43. Let timeStyle be ? GetOption(options, "timeStyle", string, « "full", "long", "medium", "short" », undefined).
  245. auto time_style = TRY(get_option(vm, *options, vm.names.timeStyle, OptionType::String, AK::Array { "full"sv, "long"sv, "medium"sv, "short"sv }, Empty {}));
  246. // 44. Set dateTimeFormat.[[TimeStyle]] to timeStyle.
  247. if (!time_style.is_undefined())
  248. date_time_format->set_time_style(time_style.as_string().utf8_string_view());
  249. // 45. If dateStyle is not undefined or timeStyle is not undefined, then
  250. if (date_time_format->has_date_style() || date_time_format->has_time_style()) {
  251. // a. If hasExplicitFormatComponents is true, then
  252. if (explicit_format_component != nullptr) {
  253. // i. Throw a TypeError exception.
  254. return vm.throw_completion<TypeError>(ErrorType::IntlInvalidDateTimeFormatOption, *explicit_format_component, "dateStyle or timeStyle"sv);
  255. }
  256. // b. If required is date and timeStyle is not undefined, then
  257. if (required == OptionRequired::Date && !time_style.is_undefined()) {
  258. // i. Throw a TypeError exception.
  259. return vm.throw_completion<TypeError>(ErrorType::IntlInvalidDateTimeFormatOption, "timeStyle"sv, "date"sv);
  260. }
  261. // c. If required is time and dateStyle is not undefined, then
  262. if (required == OptionRequired::Time && !date_style.is_undefined()) {
  263. // i. Throw a TypeError exception.
  264. return vm.throw_completion<TypeError>(ErrorType::IntlInvalidDateTimeFormatOption, "dateStyle"sv, "time"sv);
  265. }
  266. // d. Let styles be dataLocaleData.[[styles]].[[<resolvedCalendar>]].
  267. // e. Let bestFormat be DateTimeStyleFormat(dateStyle, timeStyle, styles).
  268. auto formatter = ::Locale::DateTimeFormat::create_for_date_and_time_style(
  269. date_time_format->data_locale(),
  270. time_zone,
  271. format_options.hour_cycle,
  272. format_options.hour12,
  273. date_time_format->date_style(),
  274. date_time_format->time_style());
  275. date_time_format->set_formatter(move(formatter));
  276. }
  277. // 46. Else,
  278. else {
  279. // a. Let needDefaults be true.
  280. bool needs_defaults = true;
  281. // b. If required is date or any, then
  282. if (required == OptionRequired::Date || required == OptionRequired::Any) {
  283. // i. For each property name prop of « "weekday", "year", "month", "day" », do
  284. auto check_property_value = [&](auto const& value) {
  285. // 1. Let value be formatOptions.[[<prop>]].
  286. // 2. If value is not undefined, let needDefaults be false.
  287. if (value.has_value())
  288. needs_defaults = false;
  289. };
  290. check_property_value(format_options.weekday);
  291. check_property_value(format_options.year);
  292. check_property_value(format_options.month);
  293. check_property_value(format_options.day);
  294. }
  295. // c. If required is time or any, then
  296. if (required == OptionRequired::Time || required == OptionRequired::Any) {
  297. // i. For each property name prop of « "dayPeriod", "hour", "minute", "second", "fractionalSecondDigits" », do
  298. auto check_property_value = [&](auto const& value) {
  299. // 1. Let value be formatOptions.[[<prop>]].
  300. // 2. If value is not undefined, let needDefaults be false.
  301. if (value.has_value())
  302. needs_defaults = false;
  303. };
  304. check_property_value(format_options.day_period);
  305. check_property_value(format_options.hour);
  306. check_property_value(format_options.minute);
  307. check_property_value(format_options.second);
  308. check_property_value(format_options.fractional_second_digits);
  309. }
  310. // d. If needDefaults is true and defaults is either date or all, then
  311. if (needs_defaults && (defaults == OptionDefaults::Date || defaults == OptionDefaults::All)) {
  312. // i. For each property name prop of « "year", "month", "day" », do
  313. auto set_property_value = [&](auto& value) {
  314. // 1. Set formatOptions.[[<prop>]] to "numeric".
  315. value = ::Locale::CalendarPatternStyle::Numeric;
  316. };
  317. set_property_value(format_options.year);
  318. set_property_value(format_options.month);
  319. set_property_value(format_options.day);
  320. }
  321. // e. If needDefaults is true and defaults is either time or all, then
  322. if (needs_defaults && (defaults == OptionDefaults::Time || defaults == OptionDefaults::All)) {
  323. // i. For each property name prop of « "hour", "minute", "second" », do
  324. auto set_property_value = [&](auto& value) {
  325. // 1. Set formatOptions.[[<prop>]] to "numeric".
  326. value = ::Locale::CalendarPatternStyle::Numeric;
  327. };
  328. set_property_value(format_options.hour);
  329. set_property_value(format_options.minute);
  330. set_property_value(format_options.second);
  331. }
  332. // f. Let formats be dataLocaleData.[[formats]].[[<resolvedCalendar>]].
  333. // g. If matcher is "basic", then
  334. // i. Let bestFormat be BasicFormatMatcher(formatOptions, formats).
  335. // h. Else,
  336. // i. Let bestFormat be BestFitFormatMatcher(formatOptions, formats).
  337. auto formatter = ::Locale::DateTimeFormat::create_for_pattern_options(
  338. date_time_format->data_locale(),
  339. time_zone,
  340. format_options);
  341. date_time_format->set_formatter(move(formatter));
  342. }
  343. // 47. For each row in Table 6, except the header row, in table order, do
  344. date_time_format->for_each_calendar_field_zipped_with(date_time_format->formatter().chosen_pattern(), [&](auto& date_time_format_field, auto const& best_format_field) {
  345. // a. Let prop be the name given in the Property column of the row.
  346. // b. If bestFormat has a field [[<prop>]], then
  347. if (best_format_field.has_value()) {
  348. // i. Let p be bestFormat.[[<prop>]].
  349. // ii. Set dateTimeFormat's internal slot whose name is the Internal Slot column of the row to p.
  350. date_time_format_field = best_format_field;
  351. }
  352. });
  353. // 48. If dateTimeFormat.[[Hour]] is undefined, then
  354. if (!date_time_format->hour.has_value()) {
  355. // a. Set dateTimeFormat.[[HourCycle]] to undefined.
  356. date_time_format->hour_cycle.clear();
  357. }
  358. // 49. If dateTimeFormat.[[HourCycle]] is "h11" or "h12", then
  359. // a. Let pattern be bestFormat.[[pattern12]].
  360. // b. Let rangePatterns be bestFormat.[[rangePatterns12]].
  361. // 50. Else,
  362. // a. Let pattern be bestFormat.[[pattern]].
  363. // b. Let rangePatterns be bestFormat.[[rangePatterns]].
  364. // 51. Set dateTimeFormat.[[Pattern]] to pattern.
  365. // 52. Set dateTimeFormat.[[RangePatterns]] to rangePatterns.
  366. // 53. Return dateTimeFormat.
  367. return date_time_format;
  368. }
  369. // 11.1.3 FormatOffsetTimeZoneIdentifier ( offsetMinutes ), https://tc39.es/ecma402/#sec-formatoffsettimezoneidentifier
  370. String format_offset_time_zone_identifier(double offset_minutes)
  371. {
  372. // 1. If offsetMinutes ≥ 0, let sign be the code unit 0x002B (PLUS SIGN); otherwise, let sign be the code unit 0x002D (HYPHEN-MINUS).
  373. auto sign = offset_minutes >= 0.0 ? '+' : '-';
  374. // 2. Let absoluteMinutes be abs(offsetMinutes).
  375. auto absolute_minutes = fabs(offset_minutes);
  376. // 3. Let hours be floor(absoluteMinutes / 60).
  377. auto hours = static_cast<i64>(floor(absolute_minutes / 60.0));
  378. // 4. Let minutes be absoluteMinutes modulo 60.
  379. auto minutes = static_cast<i64>(modulo(absolute_minutes, 60.0));
  380. // 5. Return the string-concatenation of sign, ToZeroPaddedDecimalString(hours, 2), the code unit 0x003A (COLON), and ToZeroPaddedDecimalString(minutes, 2).
  381. return MUST(String::formatted("{}{:02}:{:02}", sign, hours, minutes));
  382. }
  383. }