fix: stop note navigation from scaling with vault size

src/utils/noteOpenPerformance.ts

@@ -0,0 +1,106 @@
+type NoteOpenStage =
+  | 'beforeNavigateStart'
+  | 'beforeNavigateEnd'
+  | 'cacheReady'
+  | 'contentLoadStart'
+  | 'contentLoadEnd'
+  | 'editorSwapped'
+
+interface NoteOpenTrace {
+  startedAt: number
+  source: string
+  marks: Partial<Record<NoteOpenStage, number>>
+}
+
+const inFlightNoteOpens = new Map<string, NoteOpenTrace>()
+
+function isVitestRuntime(): boolean {
+  return typeof process !== 'undefined' && process.env.VITEST === 'true'
+}
+
+function canMeasurePerformance(): boolean {
+  return import.meta.env.DEV && typeof performance !== 'undefined' && !isVitestRuntime()
+}
+
+function formatDuration(durationMs: number | null): string {
+  return durationMs === null ? 'n/a' : `${durationMs.toFixed(1)}ms`
+}
+
+function measureDuration(
+  trace: NoteOpenTrace,
+  start: keyof NoteOpenTrace['marks'] | 'startedAt',
+  end: keyof NoteOpenTrace['marks'],
+): number | null {
+  const startTime = start === 'startedAt' ? trace.startedAt : trace.marks[start]
+  const endTime = trace.marks[end]
+  if (startTime === undefined || endTime === undefined) return null
+  return endTime - startTime
+}
+
+function logPerf(message: string): void {
+  if (!canMeasurePerformance()) return
+  console.debug(`[perf] ${message}`)
+}
+
+export function beginNoteOpenTrace(path: string, source: string): void {
+  if (!canMeasurePerformance()) return
+
+  const startedAt = performance.now()
+  for (const [otherPath, trace] of inFlightNoteOpens) {
+    if (otherPath === path) continue
+    logPerf(`noteOpen cancel path=${otherPath} source=${trace.source} total=${formatDuration(startedAt - trace.startedAt)} reason=superseded`)
+    inFlightNoteOpens.delete(otherPath)
+  }
+
+  inFlightNoteOpens.set(path, { startedAt, source, marks: {} })
+}
+
+export function markNoteOpenTrace(path: string, stage: NoteOpenStage): void {
+  if (!canMeasurePerformance()) return
+  const trace = inFlightNoteOpens.get(path)
+  if (!trace) return
+  trace.marks[stage] = performance.now()
+}
+
+export function finishNoteOpenTrace(path: string): void {
+  if (!canMeasurePerformance()) return
+  const trace = inFlightNoteOpens.get(path)
+  if (!trace) return
+
+  trace.marks.editorSwapped = performance.now()
+  const total = trace.marks.editorSwapped - trace.startedAt
+  const beforeNavigate = measureDuration(trace, 'beforeNavigateStart', 'beforeNavigateEnd')
+  const contentLoad = measureDuration(trace, 'contentLoadStart', 'contentLoadEnd')
+  const editorSwap = measureDuration(trace, 'contentLoadEnd', 'editorSwapped')
+    ?? measureDuration(trace, 'beforeNavigateEnd', 'editorSwapped')
+    ?? measureDuration(trace, 'startedAt', 'editorSwapped')
+
+  logPerf(
+    `noteOpen path=${path} source=${trace.source} total=${formatDuration(total)} `
+    + `beforeNavigate=${formatDuration(beforeNavigate)} `
+    + `contentLoad=${formatDuration(contentLoad)} `
+    + `editorSwap=${formatDuration(editorSwap)} `
+    + `cache=${trace.marks.cacheReady !== undefined ? 'hit' : 'miss'}`,
+  )
+  inFlightNoteOpens.delete(path)
+}
+
+export function failNoteOpenTrace(path: string, reason: string): void {
+  if (!canMeasurePerformance()) return
+  const trace = inFlightNoteOpens.get(path)
+  if (!trace) return
+
+  const total = performance.now() - trace.startedAt
+  logPerf(`noteOpen cancel path=${path} source=${trace.source} total=${formatDuration(total)} reason=${reason}`)
+  inFlightNoteOpens.delete(path)
+}
+
+export function logKeyboardNavigationTrace(
+  direction: 'up' | 'down',
+  itemCount: number,
+  durationMs: number,
+): void {
+  if (!canMeasurePerformance()) return
+  if (itemCount < 500 && durationMs < 4) return
+  logPerf(`noteListKeyboard direction=${direction} items=${itemCount} move=${formatDuration(durationMs)}`)
+}