refactor: set apollo client ssrMode only on server, use client polling

- replace manual refetch with interval with apollo client build in
  pollInterval

src/hooks/useSessionActivities/useSessionActivities.ts

@@ -10,7 +10,6 @@ import {
   useGetHostedSessionActivitiesQuery,
   GetHostedSessionActivitiesDocument,
   GetHostedSessionActivitiesQuery,
-  ActivityStatus,
 } from './types'
 import { captureException } from '@sentry/nextjs'
 
@@ -30,6 +29,7 @@ export const useSessionActivities = (): UsePathwayActivitiesHook => {
   const client = useApolloClient()
   const { data, error, loading, refetch } = useGetHostedSessionActivitiesQuery({
     variables,
+    pollInterval: POLLING_DELAY,
     onError: (error) => {
       captureException(error, {
         contexts: {
@@ -68,40 +68,6 @@ export const useSessionActivities = (): UsePathwayActivitiesHook => {
       data?.hostedSessionActivities.activities as Activity[]
     ) ?? []
 
-  // temporary solution to refetch query when subscription does not work
-  useEffect(() => {
-    let refetchQueryInterval: NodeJS.Timer | undefined
-
-    /**
-     * Note: refetch() activities can return error if we continuously
-     * call it again and again.
-     */
-
-    /**
-     * Only try to refetch activities if there are none found.
-     * That means we would only risk showing an error message
-     * when a user is waiting for activities to load, not when
-     * they are actively interacting with one.
-     */
-
-    const activeActivities = activities.filter(
-      ({ status }) => status === ActivityStatus.Active
-    )
-
-    if (activeActivities.length === 0) {
-      refetchQueryInterval = setInterval(() => {
-        refetch()
-      }, POLLING_DELAY)
-    }
-
-    if (activeActivities.length !== 0 && !isNil(refetchQueryInterval)) {
-      clearInterval(refetchQueryInterval)
-    }
-
-    // clear interval on component unmount
-    return () => clearInterval(refetchQueryInterval)
-  }, [activities])
-
   useEffect(() => {
     if (!isNil(onActivityCreated.data)) {
       const {

src/services/graphql/apollo-client.ts

@@ -87,7 +87,7 @@ export const createClient = ({
   const link = wsLink ? split(isSubscription, wsLink, defaultLink) : defaultLink
 
   return new ApolloClient({
-    ssrMode: true,
+    ssrMode: typeof window === 'undefined',
     connectToDevTools: process.env.NODE_ENV !== 'production',
     cache: new InMemoryCache(cacheConfig),
     link,