web/src/home/RotationCheck.test.tsx

@@ -1,7 +1,7 @@
 import { act, fireEvent, render, screen, waitFor, within } from '@testing-library/react'
 import { createMemoryRouter, RouterProvider } from 'react-router'
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import { clickPath, parsePushPayload } from '../push/notification.ts'
+import { clickPath, openNotification, parsePushPayload, type ClickWindow } from '../push/notification.ts'
 import { QueryClientProvider } from '@tanstack/react-query'
 import { ApiProvider, createApiClient, createQueryClient, createVerifiedSession, ME_PATH } from '../api/index.ts'
 import { createNetworkStatus } from '../pwa/networkStatus.ts'
@@ -19,6 +19,7 @@ const RAMEN = { dinner: { id: 'd8', name: 'Miso ramen', photo: null }, plan_date
 
 afterEach(() => {
   vi.unstubAllGlobals()
+  Reflect.deleteProperty(navigator, 'serviceWorker')
 })
 
 type Deferred = { resolve: (response: Response) => void; path: string; body: unknown }
@@ -53,7 +54,7 @@ function stubApi(reviews: (typeof SHAKSHUKA | typeof RAMEN)[]) {
     throw new Error(`unexpected fetch: ${init?.method ?? 'GET'} ${path}`)
   })
   vi.stubGlobal('fetch', fetchMock)
-  return { fetchMock, decisions }
+  return { fetchMock, decisions, server }
 }
 
 // decided is the server's answer to a decision on review.
@@ -244,4 +245,37 @@ describe('RotationCheck', () => {
     await renderHome(path)
     expect(within(await card()).getByText('Last night: Shakshuka')).toBeInTheDocument()
   })
+
+  it('shows the card when a rotation_review notification focuses Home already open, without a remount', async () => {
+    // navigator.serviceWorker is where the worker's postMessage to this
+    // window arrives.
+    const container = new EventTarget()
+    Object.defineProperty(navigator, 'serviceWorker', { configurable: true, value: container })
+    const { fetchMock, server } = stubApi([])
+    const reads = () => fetchMock.mock.calls.filter(([path]) => path === ROTATION_REVIEWS_PATH).length
+    await renderHome('/')
+    const home = await screen.findByRole('heading', { name: 'Pizza night' })
+    await waitFor(() => expect(reads()).toBe(1))
+    expect(screen.queryByRole('region', { name: 'Keep it in rotation?' })).not.toBeInTheDocument()
+
+    // Within the cached list's staleTime the Rotation check comes due and
+    // its notification is tapped while Home is open at /.
+    server.push(SHAKSHUKA)
+    const origin = 'https://mealquest.test'
+    const win = {
+      url: `${origin}/`,
+      focused: true,
+      focus: vi.fn(async () => {}),
+      navigate: vi.fn(async () => {}),
+      postMessage: (message) => container.dispatchEvent(new MessageEvent('message', { data: message })),
+    } satisfies ClickWindow
+    await act(() =>
+      openNotification({ url: '/' }, { matchAll: async () => [win], openWindow: vi.fn(async () => null) }, origin),
+    )
+
+    expect(win.navigate).not.toHaveBeenCalled()
+    expect(within(await card()).getByText('Last night: Shakshuka')).toBeInTheDocument()
+    expect(reads()).toBe(2)
+    expect(screen.getByRole('heading', { name: 'Pizza night' })).toBe(home)
+  })
 })

web/src/home/rotation.ts

@@ -1,7 +1,9 @@
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { useEffect } from 'react'
 import { useApi } from '../api/index.ts'
 import { isRecord } from '../api/errors.ts'
 import { photoId } from '../dinners/api.ts'
+import { isNotificationOpened } from '../push/notification.ts'
 
 export const ROTATION_REVIEWS_PATH = '/api/v1/rotation-reviews'
 export const ROTATION_REVIEWS_KEY = ['rotation-reviews'] as const
@@ -43,16 +45,29 @@ export function parseRotationReviews(where: string, body: unknown): RotationRevi
 
 // useRotationReviews is the pending Rotation checks (GET
 // /api/v1/rotation-reviews), oldest plan date first. Each mount of Home
-// reads them afresh, so Home opened from a rotation_review notification
+// reads them afresh, and so does a notification tap that focuses Home
-// shows the check it is about.
+// already open (the service worker's NotificationOpened), so Home opened
+// from a rotation_review notification shows the check it is about.
 export function useRotationReviews() {
   const { apiFetch } = useApi()
-  return useQuery({
+  const query = useQuery({
     queryKey: ROTATION_REVIEWS_KEY,
     queryFn: async () =>
       parseRotationReviews(`GET ${ROTATION_REVIEWS_PATH}`, await apiFetch<unknown>(ROTATION_REVIEWS_PATH)),
     refetchOnMount: 'always',
   })
+  const { refetch } = query
+  useEffect(() => {
+    // Without a service worker there are no notifications to tap.
+    if (!('serviceWorker' in navigator)) return
+    const container = navigator.serviceWorker
+    const onMessage = (event: MessageEvent<unknown>) => {
+      if (isNotificationOpened(event.data)) void refetch()
+    }
+    container.addEventListener('message', onMessage)
+    return () => container.removeEventListener('message', onMessage)
+  }, [refetch])
+  return query
 }
 
 // useDecideRotationReview answers "Keep it in rotation?" for a pending

web/src/push/notification.test.ts

@@ -5,6 +5,7 @@ import {
   GENERIC_NOTICE,
   appPath,
   clickPath,
+  isNotificationOpened,
   openNotification,
   parsePushPayload,
   planClick,
@@ -178,6 +179,7 @@ describe('openNotification', () => {
       focused,
       focus: vi.fn(async () => {}),
       navigate: vi.fn(async () => {}),
+      postMessage: vi.fn(),
     } satisfies ClickWindow
   }
 
@@ -193,6 +195,18 @@ describe('openNotification', () => {
     expect(win.focus).toHaveBeenCalled()
     expect(win.navigate).toHaveBeenCalledWith(`${origin}/plan/shopping`)
     expect(win.focus.mock.invocationCallOrder[0]).toBeLessThan(win.navigate.mock.invocationCallOrder[0]!)
+    expect(win.postMessage).not.toHaveBeenCalled()
+    expect(all.openWindow).not.toHaveBeenCalled()
+  })
+
+  it('focuses a window already at the url and tells it NotificationOpened instead of navigating', async () => {
+    const win = window('/', true)
+    const all = clients([win])
+    await openNotification({ url: '/' }, all, origin)
+    expect(win.focus).toHaveBeenCalled()
+    expect(win.navigate).not.toHaveBeenCalled()
+    expect(win.postMessage).toHaveBeenCalledWith({ type: 'NOTIFICATION_OPENED', url: `${origin}/` })
+    expect(isNotificationOpened(win.postMessage.mock.calls[0]![0])).toBe(true)
     expect(all.openWindow).not.toHaveBeenCalled()
   })
 

web/src/push/notification.ts

@@ -150,6 +150,18 @@ export function planClick<W extends AppWindow>(windows: readonly W[], path: stri
 export type ClickWindow = AppWindow & {
   focus(): Promise<unknown>
   navigate(url: string): Promise<unknown>
+  postMessage(message: NotificationOpened): void
+}
+
+// NotificationOpened is the message a tap posts to an open window it focuses
+// without navigating, because the window is already at url: nothing remounts
+// there, so the screen reads afresh what the notification is about.
+export type NotificationOpened = { type: 'NOTIFICATION_OPENED'; url: string }
+
+// isNotificationOpened reports whether a message from the service worker is
+// NotificationOpened.
+export function isNotificationOpened(message: unknown): message is NotificationOpened {
+  return isRecord(message) && message.type === 'NOTIFICATION_OPENED' && typeof message.url === 'string'
 }
 
 export type ClickClients<W extends ClickWindow> = {
@@ -158,7 +170,8 @@ export type ClickClients<W extends ClickWindow> = {
 }
 
 // openNotification carries out a tap on a notification with data: focus
-// first, while the tap still allows it, then navigate.
+// first, while the tap still allows it, then navigate; a window already at
+// the url is told NotificationOpened instead.
 export async function openNotification<W extends ClickWindow>(
   data: unknown,
   clients: ClickClients<W>,
@@ -171,4 +184,5 @@ export async function openNotification<W extends ClickWindow>(
   }
   await plan.window.focus()
   if (plan.navigate) await plan.window.navigate(plan.url)
+  else plan.window.postMessage({ type: 'NOTIFICATION_OPENED', url: plan.url })
 }