setProgress was called multiple times per swipe burst, each call writing
into readerStore.viewStates[key].progress. ~65 places in the reader
subtree subscribed to useReaderStore() without a selector, so every
setProgress fan-out re-rendered all of them -- even the 51 that didn't
care about progress. On Android release builds this showed up as
Layout = 9.8% and Function Call = 9.6% of main-thread self time in
Chrome DevTools' Bottom-Up profile during a reading session.
Fix:
- New tiny store store/readerProgressStore.ts holds the per-book
BookProgress map. setBookProgress only fires its own subscribers.
- readerStore.setProgress now writes progress to the new store and only
touches bookDataStore for the primary view (secondary parallel views
shouldn't overwrite the shared config).
- readerStore.getProgress is kept as a delegating facade so existing
imperative call sites don't break.
- Components / hooks that genuinely need to react to progress changes
subscribe via the new useBookProgress(bookKey) hook. The handful of
call sites that just want a one-shot read use getBookProgress(key) so
they don't subscribe at all.
- readerStore.clearViewState calls clearBookProgress so the map doesn't
grow unbounded across book opens/closes.
See store/readerProgressStore.ts header for the full rationale.
Virtualizing BooknoteView (#4352) dropped the auto-scroll that centers the
note nearest the current reading position, leaving the list stranded at the
top. The single scrollToIndex that replaced the per-item useScrollToItem was
missing the machinery TOCView already uses for virtualized auto-scroll:
- Re-apply the scroll inside the OverlayScrollbars `initialized` callback
(read via a ref): its deferred init resets the viewport scrollTop to 0, and
the lastScrolledCfiRef guard otherwise blocked any retry (reload case).
- Mount Virtuoso natively centered via initialTopMostItemIndex with a
skip-gate, so opening the panel while reading doesn't fire a scrollToIndex
that races and wedges the freshly mounted, unmeasured list (tab-switch case).
- Jump instantly (behavior 'auto') for far moves and on eink, animating
'smooth' only for short in-session updates — mirroring TOCView.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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