perf: Reduce TBT/CLS + improve a11y via layout fixes, chunked render, passive listeners, alt text#5915
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- core: batch DOM reads/writes in activity.js and turtles.js to eliminate layout thrashing (FastDOM pattern). - blocks: chunk block initialization via setTimeout to reduce Total Blocking Time (TBT). - events: apply `passive: true` to touch and wheel listeners to unblock the compositor thread. - aiwidget: implement DocumentFragment for batched DOM insertion, AudioContext singleton, and WeakMap index caching. - a11y: auto-generate descriptive `alt` tags for dynamic toolbar images.
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Hi! @walterbender |
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✅ All Jest tests passed! This PR is ready to merge. |
kartikktripathi
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Feb 26, 2026
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@walterbender LGTM.
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Summary
Targets Lighthouse: reduces Total Blocking Time (TBT) and Cumulative Layout Shift (CLS) while improving img-alt accessibility.
Changes
_makeButton,_initializePalettes, andinit()so layout measurements happen before mutations, eliminating forced synchronous layouts.blocks.loadNewBlocks()into chunks of 20 blocks viasetTimeout(0)and_processOneBlock()to yield between batches and shrink Long Tasks.{ passive: true }whereverpreventDefault()is not called, letting the browser avoid blocking scroll.<img>buttons using the button label (stripping shortcut hints) so they pass Lighthouse’simg-altrule.Testing
<img>elements passimg-alt.