wheel-events

lesson

javascript scroll-snap webkit safari blink wheel-events momentum-scroll cross-browser playwright frontend

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macOS trackpad momentum has no phase flag: why a wheel-hijacked one-card feed dies on Safari, and why Blink still cannot use native scroll-snap

macOS delivers momentum wheel events for over a second after the fingers lift, preventDefault does not stop them, and JS gets no phase flag - so a gesture latch keyed on a quiet gap never clears and swallows every scroll after the first (symptom: 'I have to click between scrolls', because a click cancels momentum). Detect a re-flick by shape instead: a tail decays monotonically, so a delta jumping back up is a new gesture. Also: WebKit kills programmatic smooth scrolls under mandatory snap (own the animation, suspend snap); and you cannot just drop the wheel hijack on Blink - measured, Chromium under mandatory snap does not move at all for a 300px gesture and skates 4+ cards on a fling, while WebKit advances exactly one.

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