Skip to content

⚡ Bolt: [성능 개선] O(N log N) Date.parse() 반복 호출을 Map-Sort-Map으로 최적화 #590

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

Draft
seonghobae wants to merge 2 commits into
base: developmental
Choose a base branch
from
Draft

⚡ Bolt: [성능 개선] O(N log N) Date.parse() 반복 호출을 Map-Sort-Map으로 최적화 #590

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
ac8f70a
perf: O(N log N) Date.parse() 호출을 Map-Sort-Map으로 최적화
seonghobae Sep 6, 2026
1e1100f
perf: O(N log N) Date.parse() 호출을 Map-Sort-Map으로 최적화
seonghobae Sep 6, 2026
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
6 changes: 6 additions & 0 deletions .jules/bolt.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,3 +3,9 @@
**Learning:** `Date.parse(value)` returns the timestamp primitive directly, while `new Date(value).getTime()` also constructs a `Date` object. Both use the same ECMAScript string-parsing semantics for these call sites.

**Action:** In frequently executed paths that only need a timestamp primitive, prefer `Date.parse(value)`. Treat the allocation reduction as a bounded micro-optimization unless a committed benchmark establishes a larger runtime effect.

## 2026-09-06 - Schwartzian transform for expensive sort comparators

**Learning:** When sorting large arrays based on an expensive data transformation like `Date.parse()` on ISO strings, placing the transformation directly inside the `Array.prototype.sort()` comparator causes it to execute O(N log N) times. A Schwartzian transform (map-sort-map) pre-computes the values in O(N) time.

**Action:** Wrap items in an object `{ original: item, parsedValue: expensiveOperation(item) }` prior to sorting when the comparator relies on computationally non-trivial operations.
11 changes: 5 additions & 6 deletions packages/web/src/components/dashboard/session-timeline-chart.tsx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -67,19 +67,18 @@ function buildChartData(
toolCalls: ToolCallPoint[],
sessionStartedAt: string
): ChartDataItem[] {
const sortedUsage = [...usageTimeline].sort(
(a, b) => Date.parse(a.timestamp) - Date.parse(b.timestamp)
)
const sortedUsage = usageTimeline
.map((item) => ({ original: item, parsedValue: Date.parse(item.timestamp) }))
.sort((a, b) => a.parsedValue - b.parsedValue)

const sortedTools = [...toolCalls].sort(
(a, b) => a.parsedTimestamp - b.parsedTimestamp
)

let toolIndex = 0
const cumulativeToolCounts = new Map<string, number>()

return sortedUsage.map((usage) => {
const currentTimestamp = Date.parse(usage.timestamp)

return sortedUsage.map(({ original: usage, parsedValue: currentTimestamp }) => {
while (
toolIndex < sortedTools.length &&
sortedTools[toolIndex]!.parsedTimestamp <= currentTimestamp
Expand Down
Loading