Skip to content

Polyfill: Fix off-by-1-or-2s error due to FP precision loss #3173

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Nov 3, 2025
Merged

Polyfill: Fix off-by-1-or-2s error due to FP precision loss #3173

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a673e03
Polyfill: Fix off-by-1-or-2s error due to FP precision loss
ptomato Oct 31, 2025
a4f979e
Update test262
ptomato Nov 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 13 additions & 3 deletions polyfill/lib/ecmascript.mjs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3927,9 +3927,19 @@ export function DifferenceTemporalZonedDateTime(operation, zonedDateTime, other,
}

export function AddTime({ hour, minute, second, millisecond, microsecond, nanosecond }, timeDuration) {
second += timeDuration.sec;
nanosecond += timeDuration.subsec;
return BalanceTime(hour, minute, second, millisecond, microsecond, nanosecond);
// timeDuration.sec is a safe integer, but second+timeDuration.sec may not be.
// minute+trunc(timeDuration.sec/60) is safe. nanosecond+timeDuration.subsec
// is also safe.
const minutes = Math.trunc(timeDuration.sec / 60);
const seconds = timeDuration.sec - minutes * 60;
return BalanceTime(
hour,
minute + minutes,
second + seconds,
millisecond,
microsecond,
nanosecond + timeDuration.subsec
);
}

export function AddInstant(epochNanoseconds, timeDuration) {
Expand Down
Loading