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ShimmerView started an infinite withRepeat sweep in an effect but never cancelled it. When the component unmounts the animation driver stays live and, through useAnimatedStyle, keeps the Animated gradient and its MaskedView subtree referenced. On web that subtree renders as an <svg> mask, so every unmounted shimmer leaks a detached SVG tree (SVGAnimatedLength/TransformList/ SMILTimeContainer seen retained by the animation-driver closure scope in heap-snapshot diffs) and pins an animation driver — the heap grows the longer the tab lives. Add the cleanup to stop the repeat on unmount, matching StatusDot and ShimmerText (which already cancel on unmount). Refs slopus#1765. Generated with [Claude Code](https://claude.ai/code) via [Happy](https://happy.engineering) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Co-Authored-By: Happy <yesreply@happy.engineering>
This was referenced Sep 17, 2026
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Problem
ShimmerViewkicks off an infinitewithRepeatsweep in auseEffectbut never cancels it. When the component unmounts, the animation driver stays live and — throughuseAnimatedStyle— keeps theAnimatedgradient and itsMaskedViewsubtree referenced.On web that
MaskedViewrenders as an<svg>mask, so every unmounted shimmer leaks a detached SVG tree and pins an animation driver. On a long-lived tab this grows the heap.Diagnosed on
happy.federicoliva.it(self-host web) via heap-snapshot diff: detached SVG objects (SVGAnimatedLength,SVGAnimatedTransformList,blink::SMILTimeContainer,SVGSVGElement) retained by the reanimated animation-driver closure scope (system / Context / scope).Same class of bug as the
StatusDotpulse (#1796).ShimmerTextalready cancels on unmount;ShimmerViewwas the one left.Fix
Return a cleanup from the effect that calls
cancelAnimation(shimmerTranslate)on unmount, so the driver stops and the gradient/mask subtree can be collected.Part of the perf work in #1765.
🤖 Generated with Claude Code