LibJS: Begin implementing the relativeTo option of Duration.round

Author: https://github.com/trflynn89
Commit: 70ad66d3c0
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2513
Reviewed-by: https://github.com/shannonbooth ✅

Libraries/LibJS/Runtime/Temporal/PlainTime.cpp

@@ -8,6 +8,8 @@
 
 #include <AK/Assertions.h>
 #include <LibJS/Runtime/AbstractOperations.h>
+#include <LibJS/Runtime/Temporal/Duration.h>
+#include <LibJS/Runtime/Temporal/Instant.h>
 #include <LibJS/Runtime/Temporal/PlainTime.h>
 #include <math.h>
 
@@ -46,6 +48,37 @@ Time noon_time_record()
     return { .days = 0, .hour = 12, .minute = 0, .second = 0, .millisecond = 0, .microsecond = 0, .nanosecond = 0 };
 }
 
+// 4.5.5 DifferenceTime ( time1, time2 ), https://tc39.es/proposal-temporal/#sec-temporal-differencetime
+TimeDuration difference_time(Time const& time1, Time const& time2)
+{
+    // 1. Let hours be time2.[[Hour]] - time1.[[Hour]].
+    auto hours = static_cast<double>(time2.hour) - static_cast<double>(time1.hour);
+
+    // 2. Let minutes be time2.[[Minute]] - time1.[[Minute]].
+    auto minutes = static_cast<double>(time2.minute) - static_cast<double>(time1.minute);
+
+    // 3. Let seconds be time2.[[Second]] - time1.[[Second]].
+    auto seconds = static_cast<double>(time2.second) - static_cast<double>(time1.second);
+
+    // 4. Let milliseconds be time2.[[Millisecond]] - time1.[[Millisecond]].
+    auto milliseconds = static_cast<double>(time2.millisecond) - static_cast<double>(time1.millisecond);
+
+    // 5. Let microseconds be time2.[[Microsecond]] - time1.[[Microsecond]].
+    auto microseconds = static_cast<double>(time2.microsecond) - static_cast<double>(time1.microsecond);
+
+    // 6. Let nanoseconds be time2.[[Nanosecond]] - time1.[[Nanosecond]].
+    auto nanoseconds = static_cast<double>(time2.nanosecond) - static_cast<double>(time1.nanosecond);
+
+    // 7. Let timeDuration be TimeDurationFromComponents(hours, minutes, seconds, milliseconds, microseconds, nanoseconds).
+    auto time_duration = time_duration_from_components(hours, minutes, seconds, milliseconds, microseconds, nanoseconds);
+
+    // 8. Assert: abs(timeDuration) < nsPerDay.
+    VERIFY(time_duration.unsigned_value() < NANOSECONDS_PER_DAY);
+
+    // 9. Return timeDuration.
+    return time_duration;
+}
+
 // 4.5.8 RegulateTime ( hour, minute, second, millisecond, microsecond, nanosecond, overflow ), https://tc39.es/proposal-temporal/#sec-temporal-regulatetime
 ThrowCompletionOr<Time> regulate_time(VM& vm, double hour, double minute, double second, double millisecond, double microsecond, double nanosecond, Overflow overflow)
 {
@@ -172,4 +205,62 @@ Time balance_time(double hour, double minute, double second, double millisecond,
     return create_time_record(hour, minute, second, millisecond, microsecond, nanosecond, delta_days);
 }
 
+// 4.5.14 CompareTimeRecord ( time1, time2 ), https://tc39.es/proposal-temporal/#sec-temporal-comparetimerecord
+i8 compare_time_record(Time const& time1, Time const& time2)
+{
+    // 1. If time1.[[Hour]] > time2.[[Hour]], return 1.
+    if (time1.hour > time2.hour)
+        return 1;
+    // 2. If time1.[[Hour]] < time2.[[Hour]], return -1.
+    if (time1.hour < time2.hour)
+        return -1;
+
+    // 3. If time1.[[Minute]] > time2.[[Minute]], return 1.
+    if (time1.minute > time2.minute)
+        return 1;
+    // 4. If time1.[[Minute]] < time2.[[Minute]], return -1.
+    if (time1.minute < time2.minute)
+        return -1;
+
+    // 5. If time1.[[Second]] > time2.[[Second]], return 1.
+    if (time1.second > time2.second)
+        return 1;
+    // 6. If time1.[[Second]] < time2.[[Second]], return -1.
+    if (time1.second < time2.second)
+        return -1;
+
+    // 7. If time1.[[Millisecond]] > time2.[[Millisecond]], return 1.
+    if (time1.millisecond > time2.millisecond)
+        return 1;
+    // 8. If time1.[[Millisecond]] < time2.[[Millisecond]], return -1.
+    if (time1.millisecond < time2.millisecond)
+        return -1;
+
+    // 9. If time1.[[Microsecond]] > time2.[[Microsecond]], return 1.
+    if (time1.microsecond > time2.microsecond)
+        return 1;
+    // 10. If time1.[[Microsecond]] < time2.[[Microsecond]], return -1.
+    if (time1.microsecond < time2.microsecond)
+        return -1;
+
+    // 11. If time1.[[Nanosecond]] > time2.[[Nanosecond]], return 1.
+    if (time1.nanosecond > time2.nanosecond)
+        return 1;
+    // 12. If time1.[[Nanosecond]] < time2.[[Nanosecond]], return -1.
+    if (time1.nanosecond < time2.nanosecond)
+        return -1;
+
+    // 13. Return 0.
+    return 0;
+}
+
+// 4.5.15 AddTime ( time, timeDuration ), https://tc39.es/proposal-temporal/#sec-temporal-addtime
+Time add_time(Time const& time, TimeDuration const& time_duration)
+{
+    auto nanoseconds = time_duration.plus(TimeDuration { static_cast<i64>(time.nanosecond) });
+
+    // 1. Return BalanceTime(time.[[Hour]], time.[[Minute]], time.[[Second]], time.[[Millisecond]], time.[[Microsecond]], time.[[Nanosecond]] + timeDuration).
+    return balance_time(time.hour, time.minute, time.second, time.millisecond, time.microsecond, nanoseconds.to_double());
+}
+
 }