Skip to content

⚡ Bolt: [performance improvement] Optimize chat messages signature generation #271

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
bobdivx wants to merge 1 commit into from
Closed

⚡ Bolt: [performance improvement] Optimize chat messages signature generation #271

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions .jules/bolt.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,3 +5,7 @@
## 2026-10-15 - [Performance] Prevent unnecessary UI array recalculations
**Learning:** In the chat component (`useThreadList`), derived state that requires filtering and sorting large arrays (like generating nested agent lists) was running synchronously on every render. Given that chat polling triggers frequent re-renders, this caused unnecessary CPU strain on lists that only rarely change.
**Action:** Use `useMemo` for derived states like `rows` and `current` in custom hooks when they involve `.filter()`, `.map()`, or `.sort()` and depend on data that updates less frequently than the component renders.

## 2026-10-23 - [Performance] Avoid `Array.join()` on hot paths for string building
**Learning:** In frequently called functions or render hooks during polling (like `messagesSignature` and `useStickToBottom`), constructing signatures using `[val1, val2, ...].join('|')` unnecessarily allocates arrays and causes garbage collection overhead. Since polling and re-renders happen continuously, these small allocations add up to noticeable memory pressure.
**Action:** Use direct template literals (e.g., `${val1}|${val2}`) for simple string concatenations in performance-critical paths instead of array mapping or joining.
12 changes: 2 additions & 10 deletions apps/web/src/components/chat/ChatThread.tsx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,16 +18,8 @@ export function useStickToBottom(messages: ChatMessage[], resetKey: unknown) {
if (!box) return;
// On ne défile que si le contenu a réellement changé.
const last = messages[messages.length - 1];
const sig = [
messages.length,
last?.content.length ?? 0,
last?.toolCalls?.length ?? 0,
last?.actions?.length ?? 0,
last?.reflections?.length ?? 0,
last?.milestones?.length ?? 0,
last?.liveLabel ?? '',
last?.streaming ? 1 : 0,
].join('|');
// Avoid Array allocation and join on hot path
const sig = `${messages.length}|${last?.content.length ?? 0}|${last?.toolCalls?.length ?? 0}|${last?.actions?.length ?? 0}|${last?.reflections?.length ?? 0}|${last?.milestones?.length ?? 0}|${last?.liveLabel ?? ''}|${last?.streaming ? 1 : 0}`;
if (sig === lastSig.current) return;
const first = lastSig.current === '';
lastSig.current = sig;
Expand Down
9 changes: 2 additions & 7 deletions apps/web/src/lib/chat-messages.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -50,13 +50,8 @@ export function messagesSignature(messages: IdentifiedMessage[]): string {
}
}

return [
messages.length,
last?.id ?? '',
last?.content.length ?? 0,
last?.toolCalls?.length ?? 0,
reactionsSig,
].join('|');
// Avoid Array allocation and join on hot path
return `${messages.length}|${last?.id ?? ''}|${last?.content.length ?? 0}|${last?.toolCalls?.length ?? 0}|${reactionsSig}`;
}

/**
Expand Down
Loading