[Fix] Call get-membership-channel only once per path name

web/components/messaging/messages-icon.tsx

@@ -1,12 +1,32 @@
 import clsx from 'clsx'
+import {PrivateMessageChannel} from 'common/supabase/private-messages'
 import {PrivateUser} from 'common/user'
 import {getNotificationDestinationsForUser} from 'common/user-notification-preferences'
 import {usePathname} from 'next/navigation'
+import {createContext, ReactNode, useContext} from 'react'
 import {BiEnvelope, BiSolidEnvelope} from 'react-icons/bi'
 import {Row} from 'web/components/layout/row'
 import {useUnseenPrivateMessageChannels} from 'web/hooks/use-private-messages'
 import {usePrivateUser} from 'web/hooks/use-user'
 
+// Shared unseen-channels state so the desktop sidebar icon and the mobile
+// bottom-nav icon (both mounted at once) consume a single fetch instead of each
+// running their own `useUnseenPrivateMessageChannels`.
+const UnseenMessageChannelsContext = createContext<PrivateMessageChannel[]>([])
+
+export function UnseenMessageChannelsProvider(props: {children: ReactNode}) {
+  const {children} = props
+  const privateUser = usePrivateUser()
+  // The hook is always called (no conditional hooks); `enabled` gates the fetch
+  // so signed-out users don't hit the authed endpoint.
+  const {unseenChannels} = useUnseenPrivateMessageChannels(false, !!privateUser)
+  return (
+    <UnseenMessageChannelsContext.Provider value={unseenChannels}>
+      {children}
+    </UnseenMessageChannelsContext.Provider>
+  )
+}
+
 export function UnseenMessagesBubble(props: {className?: string}) {
   const {className} = props
   const privateUser = usePrivateUser()
@@ -50,7 +70,7 @@ function InternalUnseenMessagesBubble(props: {
 }) {
   const {privateUser, className, bubbleClassName} = props
 
-  const {unseenChannels} = useUnseenPrivateMessageChannels(false)
+  const unseenChannels = useContext(UnseenMessageChannelsContext)
   const pathName = usePathname()
 
   const {sendToBrowser} = getNotificationDestinationsForUser(privateUser, 'new_message')

web/components/messaging/private-message-memberships-context.tsx

@@ -0,0 +1,27 @@
+import {createContext, ReactNode, useContext} from 'react'
+import {useSortedPrivateMessageMemberships} from 'web/hooks/use-private-messages'
+import {useUser} from 'web/hooks/use-user'
+
+type ChannelMembershipsValue = ReturnType<typeof useSortedPrivateMessageMemberships>
+
+const PrivateMessageMembershipsContext = createContext<ChannelMembershipsValue>({
+  channels: undefined,
+  memberIdsByChannelId: undefined,
+})
+
+export const usePrivateMessageMembershipsContext = () =>
+  useContext(PrivateMessageMembershipsContext)
+
+// Fetches the current user's channel memberships once and shares them via
+// context so the many SendMessageButtons on a page (one per profile card) don't
+// each call get-channel-memberships.
+export function PrivateMessageMembershipsProvider(props: {children: ReactNode}) {
+  const {children} = props
+  const currentUser = useUser()
+  const channelMemberships = useSortedPrivateMessageMemberships(currentUser?.id)
+  return (
+    <PrivateMessageMembershipsContext.Provider value={channelMemberships}>
+      {children}
+    </PrivateMessageMembershipsContext.Provider>
+  )
+}

web/components/messaging/send-message-button.tsx

@@ -11,10 +11,10 @@ import {CommentInputTextArea} from 'web/components/comments/comment-input'
 import {Col} from 'web/components/layout/col'
 import {Modal, MODAL_CLASS} from 'web/components/layout/modal'
 import {EmailVerificationPrompt} from 'web/components/messaging/email-verification-prompt'
+import {usePrivateMessageMembershipsContext} from 'web/components/messaging/private-message-memberships-context'
 import {useTextEditor} from 'web/components/widgets/editor'
 import {Tooltip} from 'web/components/widgets/tooltip'
 import {useFirebaseUser} from 'web/hooks/use-firebase-user'
-import {useSortedPrivateMessageMemberships} from 'web/hooks/use-private-messages'
 import {usePrivateUser, useUser} from 'web/hooks/use-user'
 import {api} from 'web/lib/api'
 import {firebaseLogin} from 'web/lib/firebase/users'
@@ -50,8 +50,7 @@ export const SendMessageButton = (props: {
   const router = useRouter()
   const privateUser = usePrivateUser()
   const currentUser = useUser()
-  const channelMemberships = useSortedPrivateMessageMemberships(currentUser?.id)
-  const {memberIdsByChannelId} = channelMemberships
+  const {memberIdsByChannelId} = usePrivateMessageMembershipsContext()
   const t = useT()
 
   const [openComposeModal, setOpenComposeModal] = useState(false)

web/hooks/use-api-getter.ts

@@ -12,10 +12,10 @@ const promiseCache: Record<string, Promise<any> | undefined> = {}
 export const useAPIGetter = <P extends APIPath>(
   path: P,
   props: APIParams<P> | undefined,
-  ingoreDependencies?: string[],
+  ignoreDependencies?: string[],
 ) => {
   const propsStringToTriggerRefresh = JSON.stringify(
-    deepCopyWithoutKeys(props, ingoreDependencies || []),
+    deepCopyWithoutKeys(props, ignoreDependencies || []),
   )
 
   // Key caching and in-flight dedup on the dependency-filtered props so that

web/hooks/use-private-messages.ts

@@ -58,7 +58,7 @@ export function usePrivateMessages(channelId: number, limit: number, userId: str
   return {messages, fetchMessages, setMessages}
 }
 
-export const useUnseenPrivateMessageChannels = (ignorePageSeenTime: boolean) => {
+export const useUnseenPrivateMessageChannels = (ignorePageSeenTime: boolean, enabled = true) => {
   const pathName = usePathname()
   const lastSeenMessagesPageTime = useLastSeenMessagesPageTime() // ms for now
   const [lastSeenChatTimeByChannelId, setLastSeenChatTimeByChannelId] = useState<
@@ -67,12 +67,14 @@ export const useUnseenPrivateMessageChannels = (ignorePageSeenTime: boolean) =>
 
   const {data, refresh} = useAPIGetter(
     'get-channel-memberships',
-    {
-      lastUpdatedTime: ignorePageSeenTime
-        ? new Date(0).toISOString()
-        : millisToTs(lastSeenMessagesPageTime),
-      limit: 100,
-    },
+    enabled
+      ? {
+          lastUpdatedTime: ignorePageSeenTime
+            ? new Date(0).toISOString()
+            : millisToTs(lastSeenMessagesPageTime),
+          limit: 100,
+        }
+      : undefined,
     ['lastUpdatedTime'],
   )
   const {channels} = data ?? {

web/pages/_app.tsx

@@ -21,6 +21,8 @@ import {useEffect, useState} from 'react'
 import {AuthProvider, AuthUser} from 'web/components/auth-context'
 import {ErrorBoundary} from 'web/components/error-boundary'
 import {LiveRegionProvider} from 'web/components/live-region'
+import {UnseenMessageChannelsProvider} from 'web/components/messaging/messages-icon'
+import {PrivateMessageMembershipsProvider} from 'web/components/messaging/private-message-memberships-context'
 import {ChoicesProvider} from 'web/hooks/use-choices'
 import {useFontPreferenceManager} from 'web/hooks/use-font-preference'
 import {useHasLoaded} from 'web/hooks/use-has-loaded'
@@ -237,9 +239,13 @@ function MyApp(props: AppProps<PageProps>) {
                     <ChoicesProvider>
                       <PinnedQuestionIdsProvider>
                         <HiddenProfilesProvider>
-                          <WebPush />
-                          <AndroidPush />
-                          <Component {...pageProps} />
+                          <UnseenMessageChannelsProvider>
+                            <PrivateMessageMembershipsProvider>
+                              <WebPush />
+                              <AndroidPush />
+                              <Component {...pageProps} />
+                            </PrivateMessageMembershipsProvider>
+                          </UnseenMessageChannelsProvider>
                         </HiddenProfilesProvider>
                       </PinnedQuestionIdsProvider>
                     </ChoicesProvider>