Stop re-parsing dates in isStatusStillActive (#11574)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

src/features/liveNow/index.tsx

@@ -6,7 +6,6 @@ import {moderateStatus} from '@bsky/sdk/moderation'
 import {msg} from '@lingui/core/macro'
 import {useLingui} from '@lingui/react'
 import {useMutation, useQuery, useQueryClient} from '@tanstack/react-query'
-import {isAfter, parseISO} from 'date-fns'
 
 import {uploadBlob} from '#/lib/api'
 import {imageToThumb} from '#/lib/api/resolve'
@@ -23,7 +22,11 @@ import {useTickEveryMinute} from '#/state/shell'
 import {useDialogContext} from '#/components/Dialog'
 import * as Toast from '#/components/Toast'
 import {useAnalytics} from '#/analytics'
-import {getLiveNowHost, getLiveServiceNames} from '#/features/liveNow/utils'
+import {
+  getLiveNowHost,
+  getLiveServiceNames,
+  isStatusStillActive,
+} from '#/features/liveNow/utils'
 import {app, com} from '#/lexicons'
 import * as bsky from '#/types/bsky'
 
@@ -151,14 +154,6 @@ export function useActorStatus(actor?: bsky.profile.AnyProfileView) {
   }, [shadowed, config, tick, moderation])
 }
 
-export function isStatusStillActive(timeStr: string | undefined) {
-  if (!timeStr) return false
-  const now = new Date()
-  const expiry = parseISO(timeStr)
-
-  return isAfter(expiry, now)
-}
-
 /**
  * Validates whether the live status is valid for display in the app. Does NOT
  * validate if the status is valid for the acting user e.g. as they go live.

src/features/liveNow/isStatusStillActive.test.ts

@@ -0,0 +1,35 @@
+import {isStatusStillActive} from '#/features/liveNow/utils'
+
+describe('isStatusStillActive', () => {
+  const iso = (offsetMs: number) =>
+    new Date(Date.now() + offsetMs).toISOString()
+
+  it('is active for a future expiry', () => {
+    expect(isStatusStillActive(iso(60_000))).toBe(true)
+  })
+
+  it('is not active for a past expiry', () => {
+    expect(isStatusStillActive(iso(-60_000))).toBe(false)
+  })
+
+  it('is not active without a value', () => {
+    expect(isStatusStillActive(undefined)).toBe(false)
+    expect(isStatusStillActive('')).toBe(false)
+  })
+
+  /*
+   * The predicate reads an atproto `datetime`, which always carries an offset.
+   * An unparseable value yields NaN, and every NaN comparison is false, so a
+   * bad timestamp reads as "not live" rather than throwing or showing a stale
+   * live badge.
+   */
+  it('is not active for an unparseable value', () => {
+    expect(isStatusStillActive('not-a-date')).toBe(false)
+  })
+
+  it('handles offsets and fractional seconds', () => {
+    const future = new Date(Date.now() + 3_600_000)
+    expect(isStatusStillActive(future.toISOString())).toBe(true)
+    expect(isStatusStillActive('2000-01-01T00:00:00.123+00:00')).toBe(false)
+  })
+})

src/features/liveNow/utils.ts

@@ -97,3 +97,16 @@ export function getLiveNowHost(url: string) {
   const {hostname} = new URL(url)
   return sanitizeLiveNowHost(hostname)
 }
+
+/**
+ * Whether a live status has not yet expired.
+ *
+ * Called per post, per render while scrolling, so this stays on primitives -
+ * `parseISO` plus two `Date` objects showed up in the scroll profile.
+ * `Date.parse` returns `NaN` for an unparseable value and `NaN > n` is `false`,
+ * which is the same "not active" answer the date-fns version gave.
+ */
+export function isStatusStillActive(timeStr: string | undefined) {
+  if (!timeStr) return false
+  return Date.parse(timeStr) > Date.now()
+}