Revert "Disable DateTimeFormat::formatToParts for Apple platform (#1155…

…)" (#1567)

Summary:
This reverts commit c5a633f.

That commit removed the Intl.DateTimeFormat.formatToParts for Apple platforms from Hermes.
However, the community started depending on it, and we ended up manually reverting that commit in the release branch for the past 3 releases.

This is like reverting the commit in main, so we are proceeding with that approach to simplify the release process of React Native and Hermes to the OSS.

Pull Request resolved: #1567

Test Plan: CI

Reviewed By: blakef

Differential Revision: D66099176

Pulled By: cipolleschi

fbshipit-source-id: fe42bab7308bbd2294911be694f0bef8d1652566

doc/IntlAPIs.md

@@ -50,7 +50,6 @@ One popular implementation strategy followed by other engines, is to bundle an i
 ## Supported on Android only
 - `Intl.NumberFormat`
   - `Intl.NumberFormat.prototype.formatToParts`
-  - `Intl.DateTimeFormat.prototype.formatToParts`
 
 ## * Limitations on property support
 

lib/Platform/Intl/PlatformIntlApple.mm

@@ -1262,6 +1262,8 @@ uint8_t getCurrencyDigits(std::u16string_view code) {
 
   std::u16string format(double jsTimeValue) noexcept;
 
+  std::vector<Part> formatToParts(double x) noexcept;
+
  private:
   void initializeNSDateFormatter(NSLocale *nsLocale) noexcept;
 
@@ -1932,8 +1934,76 @@ uint8_t getCurrencyDigits(std::u16string_view code) {
   return static_cast<DateTimeFormatApple *>(this)->format(jsTimeValue);
 }
 
+static std::u16string returnTypeOfDate(const char16_t &c16) {
+  if (c16 == u'a')
+    return u"dayPeriod";
+  if (c16 == u'z' || c16 == u'v' || c16 == u'O')
+    return u"timeZoneName";
+  if (c16 == u'G')
+    return u"era";
+  if (c16 == u'y')
+    return u"year";
+  if (c16 == u'M')
+    return u"month";
+  if (c16 == u'E')
+    return u"weekday";
+  if (c16 == u'd')
+    return u"day";
+  if (c16 == u'h' || c16 == u'k' || c16 == u'K' || c16 == u'H')
+    return u"hour";
+  if (c16 == u'm')
+    return u"minute";
+  if (c16 == u's')
+    return u"second";
+  if (c16 == u'S')
+    return u"fractionalSecond";
+  return u"literal";
+}
+
+// Implementer note: This method corresponds roughly to
+// https://402.ecma-international.org/8.0/#sec-formatdatetimetoparts
+std::vector<Part> DateTimeFormatApple::formatToParts(double x) noexcept {
+  // NOTE: We dont have access to localeData.patterns. Instead we use
+  // NSDateFormatter's foramt string, and break it into components.
+  // 1. Let parts be ? PartitionDateTimePattern(dateTimeFormat, x).
+  auto fmt = nsStringToU16String(nsDateFormatter_.dateFormat);
+  std::unique(fmt.begin(), fmt.end());
+  auto formattedDate = format(x);
+  // 2. Let result be ArrayCreate(0).
+  std::vector<Part> result;
+  // 3. Let n be 0.
+  // 4. For each Record { [[Type]], [[Value]] } part in parts, do
+  // a. Let O be OrdinaryObjectCreate(%Object.prototype%).
+  // b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
+  // c. Perform ! CreateDataPropertyOrThrow(O, "value", part.[[Value]]).
+  // d. Perform ! CreateDataProperty(result, ! ToString(n), O).
+  // e. Increment n by 1.
+  std::u16string currentPart;
+  unsigned n = 0;
+  static auto alphanumerics = NSCharacterSet.alphanumericCharacterSet;
+  for (char16_t c16 : formattedDate) {
+    if ([alphanumerics characterIsMember:c16]) {
+      currentPart += c16;
+      continue;
+    }
+    if (currentPart != u"") {
+      result.push_back(
+          {{u"type", returnTypeOfDate(fmt[n])}, {u"value", currentPart}});
+      currentPart = u"";
+      n++;
+    }
+    result.push_back({{u"type", u"literal"}, {u"value", {c16}}});
+    n++;
+  }
+  // Last format string component.
+  result.push_back(
+      {{u"type", returnTypeOfDate(fmt[n])}, {u"value", currentPart}});
+  // 5. Return result.
+  return result;
+}
+
 std::vector<Part> DateTimeFormat::formatToParts(double x) noexcept {
-  llvm_unreachable("formatToParts is unimplemented on Apple platforms");
+  return static_cast<DateTimeFormatApple *>(this)->formatToParts(x);
 }
 
 class NumberFormatApple : public NumberFormat {

lib/VM/JSLib/Intl.cpp

@@ -929,15 +929,13 @@ void defineIntlDateTimeFormat(Runtime &runtime, Handle<JSObject> intl) {
       false,
       true);
 
-#ifndef __APPLE__
   defineMethod(
       runtime,
       prototype,
       Predefined::getSymbolID(Predefined::formatToParts),
       nullptr,
       intlDateTimeFormatPrototypeFormatToParts,
       1);
-#endif
 
   defineMethod(
       runtime,

test/hermes/intl/date-time-format-apple.js

@@ -150,5 +150,24 @@ print(new Intl.DateTimeFormat('en-US').resolvedOptions().numberingSystem);
 print(new Intl.DateTimeFormat('en-US', { timeZone: 'SGT'}).resolvedOptions().timeZone);
 // CHECK-NEXT: SGT
 
+print(JSON.stringify(new Intl.DateTimeFormat('en-US').formatToParts(date)));
+// CHECK-NEXT: [{"value":"1","type":"month"},{"value":"/","type":"literal"},{"value":"2","type":"day"},{"value":"/","type":"literal"},{"value":"2020","type":"year"}]
+
+print(JSON.stringify(new Intl.DateTimeFormat('en-GB').formatToParts(date)));
+// CHECK-NEXT: [{"value":"02","type":"day"},{"value":"/","type":"literal"},{"value":"01","type":"month"},{"value":"/","type":"literal"},{"value":"2020","type":"year"}]
+
+print(JSON.stringify(new Intl.DateTimeFormat('en-US', {weekday: 'long',
+  year: 'numeric',
+  month: 'numeric',
+  day: 'numeric',
+  hour: 'numeric',
+  minute: 'numeric',
+  second: 'numeric',
+  fractionalSecondDigits: 3,
+  hour12: true,
+  timeZone: 'UTC'
+}).formatToParts(new Date(Date.UTC(2020, 0, 2, 3, 45, 00, 30)))));
+// CHECK-NEXT: [{"value":"Thursday","type":"weekday"},{"value":",","type":"literal"},{"value":" ","type":"literal"},{"value":"1","type":"month"},{"value":"/","type":"literal"},{"value":"2","type":"day"},{"value":"/","type":"literal"},{"value":"2020","type":"year"},{"value":",","type":"literal"},{"value":" ","type":"literal"},{"value":"3","type":"hour"},{"value":":","type":"literal"},{"value":"45","type":"minute"},{"value":":","type":"literal"},{"value":"00","type":"second"},{"value":".","type":"literal"},{"value":"030","type":"fractionalSecond"},{"value":" ","type":"literal"},{"value":"AM","type":"dayPeriod"}]
+
 print(new Date(Date.UTC(2020, 0, 2)).toLocaleString("en-US", {weekday: "short", timeZone: "UTC"}))
 // CHECK-NEXT: Thu

test/hermes/intl/intl.js

@@ -83,9 +83,7 @@ testServiceGetterTypes(Intl.DateTimeFormat, 'format');
 testServiceMethodTypes(Intl.DateTimeFormat, 'formatToParts');
 testServiceMethodTypes(Intl.DateTimeFormat, 'resolvedOptions');
 assert(typeof Intl.DateTimeFormat().format() === 'string');
-if(Intl.DateTimeFormat.prototype.formatToParts) {
-  testParts(Intl.DateTimeFormat().formatToParts());
-}
+testParts(Intl.DateTimeFormat().formatToParts());
 
 testServiceTypes(Intl.NumberFormat);
 testServiceGetterTypes(Intl.NumberFormat, 'format');

utils/testsuite/testsuite_skiplist.py

@@ -1113,7 +1113,11 @@
     "test262/test/intl402/DateTimeFormat/prototype/resolvedOptions/order-dayPeriod.js",
     "test262/test/intl402/DateTimeFormat/prototype/resolvedOptions/hourCycle-timeStyle.js",
     "test262/test/intl402/DateTimeFormat/prototype/resolvedOptions/order-style.js",
-    "test262/test/intl402/DateTimeFormat/prototype/formatToParts",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/related-year-zh.js",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/dayPeriod-narrow-en.js",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/dayPeriod-long-en.js",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/dayPeriod-short-en.js",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/fractionalSecondDigits.js",
     "test262/test/intl402/DateTimeFormat/prototype/format/timedatestyle-en.js",
     "test262/test/intl402/DateTimeFormat/prototype/format/dayPeriod-long-en.js",
     "test262/test/intl402/DateTimeFormat/prototype/format/dayPeriod-narrow-en.js",
@@ -1123,6 +1127,7 @@
     # This test assumes that "year" has some default value. That is an implementation-defined behavior.
     # In our case it remains undefined, which causes this test to fail.
     "test262/test/intl402/DateTimeFormat/default-options-object-prototype.js",
+    "test262/test/intl402/DateTimeFormat/prototype/formatToParts/related-year.js",
     "test262/test/intl402/DateTimeFormat/prototype/format/proleptic-gregorian-calendar.js",
     "test262/test/intl402/DateTimeFormat/prototype/formatRange",
     "test262/test/intl402/DateTimeFormat/prototype/formatRangeToParts",
@@ -1954,11 +1959,13 @@
         "test262/test/intl402/NumberFormat",
         "test262/test/intl402/String/prototype/toLocaleLowerCase",
         "test262/test/intl402/String/prototype/toLocaleUpperCase",
+        "test262/test/intl402/DateTimeFormat/prototype/formatToParts",
     ],
     "darwin": [
         # Intl implementation issues on Apple.
         "test262/test/intl402/Collator/ignore-invalid-unicode-ext-values.js",
         "test262/test/intl402/Collator/unicode-ext-value-collation.js",
+        "test262/test/intl402/DateTimeFormat/prototype/formatToParts/offset-timezone-correct.js",
     ],
 }