⚡ Bolt: Optimized scroll event listeners and DOM queries#124
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- Added state tracking to `scrollTopBtn` visibility logic to prevent redundant `classList` mutations on every frame.
- Added `{ passive: true }` to `scrollTopBtn` listener for non-blocking scrolling.
- Added state tracking to `navBtns` active class logic to only update the DOM when the active section changes.
- Cached `#systemTime` lookup in `updateSystemTime` to prevent O(N) DOM querying.
Co-authored-by: kaitoartz <56949089+kaitoartz@users.noreply.github.com>
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💡 What:
isScrollTopVisibleandcurrentActiveBtn) to scroll event listeners injs/script.js.{ passive: true }to thescrollTopBtnscroll event listener.#systemTimeDOM lookup outside of theupdateSystemTimeperiodic function.🎯 Why:
Unconditional DOM mutations (
classList.add/remove) inside high-frequency scroll handlers cause layout thrashing and unnecessary CPU overhead. Similarly, querying the DOM on every interval tick wastes CPU resources over time. Passive event listeners ensure the browser can scroll smoothly without waiting for the JS event loop to complete.📊 Impact:
Eliminates layout thrashing and redundant DOM writes during scrolling. Removes an O(N) DOM lookup that fired every second. Improves overall scroll framerate and reduces background CPU/battery usage.
🔬 Measurement:
Check
index.htmlin the browser, verify that scrolling up and down properly reveals the scroll-to-top button and updates the active nav link, and check the system time updates accurately. Use DevTools Performance tab to observe fewer DOM updates and style recalculations during scrolling.PR created automatically by Jules for task 4674792295466490664 started by @kaitoartz