Skip to content

⚡ Bolt: Optimize chat signatures by replacing array joins with string concatenation #290

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: Optimize chat signatures by replacing array joins with string concatenation #290

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.

## 2026-10-29 - [Performance] Optimize Chat Signature Generation Hot Paths
**Learning:** In chat signature generation functions (like `messagesSignature` and `useStickToBottom`), array instantiation combined with `.join('|')` causes unnecessary memory allocation overhead during frequent polling or render cycles.
**Action:** Replace `Array.prototype.join()` with direct string concatenation on hot paths where signatures are generated frequently.
26 changes: 16 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 +18,22 @@ 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('|');
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
18 changes: 11 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 +50,17 @@ export function messagesSignature(messages: IdentifiedMessage[]): string {
}
}

return [
messages.length,
last?.id ?? '',
last?.content.length ?? 0,
last?.toolCalls?.length ?? 0,
reactionsSig,
].join('|');
return (
messages.length +
'|' +
(last?.id ?? '') +
'|' +
(last?.content.length ?? 0) +
'|' +
(last?.toolCalls?.length ?? 0) +
'|' +
reactionsSig
);
}

/**
Expand Down
Loading