⚡ Bolt: [performance improvement] Optimize React list rendering in ProgressPanel and LogPanel#138
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💡 What: - Extracted list items in `ProgressPanel` and `LogPanel` into `React.memo` components (`DownloadItem` and `LogItem`). - Moved static format helpers (`formatSpeed`, `formatETA`, `getStatusColor`, `getLogColor`) outside the component bodies. - Generated client-side stable `id`s for `LogMessage`s to use as React keys instead of array indices. - Added custom equality function to `DownloadItem`'s `React.memo` to compare primitive output fields. 🎯 Why: - During high-frequency WebSocket updates (logs arriving every few milliseconds), appending items to a state array triggered an `O(N)` re-render for every existing item in the list. This caused significant UI lag as the download progressed and logs accumulated. 📊 Impact: - Transforms rendering complexity from `O(N)` to `O(1)` per new message. Existing items in the list no longer re-render unnecessarily when a new item is appended. 🔬 Measurement: - Start a large download. - Open React DevTools Profiler. - Observe that as logs and progress updates fly in, only the new rows and the specific progress rows being updated flash/re-render, instead of the entire list container and every child element. Co-authored-by: dzp5103 <214723817+dzp5103@users.noreply.github.com>
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💡 What:
ProgressPanelandLogPanelintoReact.memocomponents (DownloadItemandLogItem).formatSpeed,formatETA,getStatusColor,getLogColor) outside the component bodies.ids forLogMessages to use as React keys instead of array indices.DownloadItem'sReact.memoto compare primitive output fields.🎯 Why:
O(N)re-render for every existing item in the list. This caused significant UI lag as the download progressed and logs accumulated.📊 Impact:
O(N)toO(1)per new message. Existing items in the list no longer re-render unnecessarily when a new item is appended.🔬 Measurement:
PR created automatically by Jules for task 18023903420292637628 started by @dzp5103