From 4640643019f861e9c46c98cf04e69c11975d03d8 Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Sun, 1 Aug 2021 17:59:20 +0100
Subject: [PATCH] LibJS: Handle ZonedDateTime in ToTemporalDate

---
 .../LibJS/Runtime/Temporal/PlainDate.cpp      | 21 +++++++++++++++----
 .../Temporal/PlainDate/PlainDate.from.js      | 17 +++++++++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDate.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDate.cpp
index 9259d168d5..d5113409ff 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDate.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDate.cpp
@@ -8,10 +8,13 @@
 #include <LibJS/Runtime/AbstractOperations.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
+#include <LibJS/Runtime/Temporal/Instant.h>
 #include <LibJS/Runtime/Temporal/PlainDate.h>
 #include <LibJS/Runtime/Temporal/PlainDateConstructor.h>
 #include <LibJS/Runtime/Temporal/PlainDateTime.h>
 #include <LibJS/Runtime/Temporal/PlainYearMonth.h>
+#include <LibJS/Runtime/Temporal/TimeZone.h>
+#include <LibJS/Runtime/Temporal/ZonedDateTime.h>
 
 namespace JS::Temporal {
 
@@ -89,10 +92,20 @@ PlainDate* to_temporal_date(GlobalObject& global_object, Value item, Object* opt
         }
 
         // b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
-        // i. Let instant be ! CreateTemporalInstant(item.[[Nanoseconds]]).
-        // ii. Let plainDateTime be ? BuiltinTimeZoneGetPlainDateTimeFor(item.[[TimeZone]], instant, item.[[Calendar]]).
-        // iii. Return ! CreateTemporalDate(plainDateTime.[[ISOYear]], plainDateTime.[[ISOMonth]], plainDateTime.[[ISODay]], plainDateTime.[[Calendar]]).
-        // TODO
+        if (is<ZonedDateTime>(item_object)) {
+            auto& zoned_date_time = static_cast<ZonedDateTime&>(item_object);
+
+            // i. Let instant be ! CreateTemporalInstant(item.[[Nanoseconds]]).
+            auto* instant = create_temporal_instant(global_object, zoned_date_time.nanoseconds());
+
+            // ii. Let plainDateTime be ? BuiltinTimeZoneGetPlainDateTimeFor(item.[[TimeZone]], instant, item.[[Calendar]]).
+            auto* plain_date_time = builtin_time_zone_get_plain_date_time_for(global_object, &zoned_date_time.time_zone(), *instant, zoned_date_time.calendar());
+            if (vm.exception())
+                return {};
+
+            // iii. Return ! CreateTemporalDate(plainDateTime.[[ISOYear]], plainDateTime.[[ISOMonth]], plainDateTime.[[ISODay]], plainDateTime.[[Calendar]]).
+            return create_temporal_date(global_object, plain_date_time->iso_year(), plain_date_time->iso_month(), plain_date_time->iso_day(), plain_date_time->calendar());
+        }
 
         // c. If item has an [[InitializedTemporalDateTime]] internal slot, then
         if (is<PlainDateTime>(item_object)) {
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.from.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.from.js
index d6f5730656..6519880961 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.from.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.from.js
@@ -11,6 +11,23 @@ describe("correct behavior", () => {
         expect(createdPlainDate.day).toBe(26);
     });
 
+    test("PlainDateTime instance argument", () => {
+        const plainDateTime = new Temporal.PlainDateTime(2021, 7, 26, 1, 2, 3);
+        const createdPlainDate = Temporal.PlainDate.from(plainDateTime);
+        expect(createdPlainDate.year).toBe(2021);
+        expect(createdPlainDate.month).toBe(7);
+        expect(createdPlainDate.day).toBe(26);
+    });
+
+    test("ZonedDateTime instance argument", () => {
+        const timeZone = new Temporal.TimeZone("UTC");
+        const zonedDateTime = new Temporal.ZonedDateTime(1627318123456789000n, timeZone);
+        const createdPlainDate = Temporal.PlainDate.from(zonedDateTime);
+        expect(createdPlainDate.year).toBe(2021);
+        expect(createdPlainDate.month).toBe(7);
+        expect(createdPlainDate.day).toBe(26);
+    });
+
     // Un-skip once ParseISODateTime & ParseTemporalDateString are implemented
     test.skip("PlainDate string argument", () => {
         const createdPlainDate = Temporal.PlainDate.from("2021-07-26");