LibJS: Remove unnecessary modulo operation in GetISOPartsFromEpoch

This is an editorial change in the Temporal spec.

See: https://github.com/tc39/proposal-temporal/commit/fc3f80d

1 files changed, 7 insertions, 4 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
index 4248f74ef8..74be2f637e 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp
@@ -136,13 +136,16 @@ ISODateTime get_iso_parts_from_epoch(GlobalObject& global_object, Crypto::Signed
     // 10. Let millisecond be ℝ(! msFromTime(epochMilliseconds)).
     auto millisecond = ms_from_time(epoch_milliseconds);
 
-    // 11. Let microsecond be floor(remainderNs / 1000) modulo 1000.
-    auto microsecond = modulo(floor(remainder_ns / 1000), 1000);
+    // 11. Let microsecond be floor(remainderNs / 1000).
+    auto microsecond = floor(remainder_ns / 1000);
 
-    // 12. Let nanosecond be remainderNs modulo 1000.
+    // 12. Assert: microsecond < 1000.
+    VERIFY(microsecond < 1000);
+
+    // 13. Let nanosecond be remainderNs modulo 1000.
     auto nanosecond = modulo(remainder_ns, 1000);
 
-    // 13. Return the Record { [[Year]]: year, [[Month]]: month, [[Day]]: day, [[Hour]]: hour, [[Minute]]: minute, [[Second]]: second, [[Millisecond]]: millisecond, [[Microsecond]]: microsecond, [[Nanosecond]]: nanosecond }.
+    // 14. Return the Record { [[Year]]: year, [[Month]]: month, [[Day]]: day, [[Hour]]: hour, [[Minute]]: minute, [[Second]]: second, [[Millisecond]]: millisecond, [[Microsecond]]: microsecond, [[Nanosecond]]: nanosecond }.
     return { .year = year, .month = month, .day = day, .hour = hour, .minute = minute, .second = second, .millisecond = millisecond, .microsecond = static_cast<u16>(microsecond), .nanosecond = static_cast<u16>(nanosecond) };
 }