Opening Continuous stayed slow, and the slowness tracked the number of enabled
calendars rather than the window size — which pointed past the provider query to
the layout behind it.
layoutCalendarWeek opens by filtering the instances it is handed down to the
ones touching its seven days. For a single month's grid that is nothing; for the
scrolling styles it was a scan of every instance in an eleven-month window,
repeated for each of a hundred-odd rows, with a time-zone conversion per check.
The work grew with events × rows, so switching every calendar on multiplied it.
- DayIndex buckets the window's events by the dates they cover, once, and each
row takes the handful on its own seven days. Membership is decided by
coversDay itself rather than re-derived from the timestamps — the all-day and
timed cases have enough edge cases between them (UTC anchoring, exclusive
ends, zero-length events at midnight) that a second implementation would
drift. DayIndexTest pins row-for-row equality with the old full scan, in a
zone east of UTC.
- Only the style on screen is laid out. Adding Dense had quietly doubled the
work, since both layouts were built from every load and one was always thrown
away.
- The paged flow no longer queries under a scrolling style, mirroring the gate
the scrolling flow already had.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Jean-Luc Makiola
b417900ddd