source snapshot 2026-09-02

tests/e2e/artificial-opencode-scroll-measurement.ts

@@ -0,0 +1,75 @@
+export type ScrollAttemptMeasurement = {
+  name: string
+  actionMs: number
+  observeMs: number
+  beforeViewportY: number
+  afterActionViewportY: number
+  afterViewportY: number
+  beforeScrollTop: number | null
+  afterActionScrollTop: number | null
+  afterScrollTop: number | null
+  error?: string
+}
+
+export type ResponsiveScrollPath = {
+  name: string
+  latencyMs: number
+}
+
+type ScrollMeasurementLike = {
+  scrollLatencyMs: number
+  beforeViewportY: number
+  afterViewportY: number
+  attempts: ScrollAttemptMeasurement[]
+}
+
+export function formatScrollAttempts(attempts: ScrollAttemptMeasurement[]): string {
+  return attempts
+    .map(
+      (attempt) =>
+        `${attempt.name}:${attempt.beforeViewportY}>${attempt.afterActionViewportY}>${
+          attempt.afterViewportY
+        }` +
+        `(${formatNullableNumber(attempt.beforeScrollTop)}>${formatNullableNumber(
+          attempt.afterActionScrollTop
+        )}>${formatNullableNumber(
+          attempt.afterScrollTop
+        )};action=${attempt.actionMs.toFixed(1)};observe=${attempt.observeMs.toFixed(1)})${
+          attempt.error ? ':error' : ''
+        }`
+    )
+    .join(',')
+}
+
+export function getResponsiveScrollPath(
+  measurement: ScrollMeasurementLike
+): ResponsiveScrollPath | null {
+  let best: ResponsiveScrollPath | null = null
+  const recordCandidate = (candidate: ResponsiveScrollPath): void => {
+    if (!best || candidate.latencyMs < best.latencyMs) {
+      best = candidate
+    }
+  }
+
+  const cdpWheel = measurement.attempts.find((attempt) => attempt.name === 'cdpWheel')
+  if (cdpWheel && cdpWheel.afterViewportY < cdpWheel.beforeViewportY) {
+    recordCandidate({
+      name: cdpWheel.name,
+      latencyMs: measurement.scrollLatencyMs
+    })
+  }
+  for (const attempt of measurement.attempts) {
+    if (attempt.name === 'cdpWheel' || attempt.afterViewportY >= attempt.beforeViewportY) {
+      continue
+    }
+    recordCandidate({
+      name: attempt.name,
+      latencyMs: attempt.actionMs + attempt.observeMs
+    })
+  }
+  return best
+}
+
+function formatNullableNumber(value: number | null): string {
+  return value === null ? 'na' : value.toFixed(0)
+}