From 2f9fadd5f8dc7fbc840e2e56f98b3340c721b808 Mon Sep 17 00:00:00 2001
From: Andrew Bulat <andrii.bulat@gmail.com>
Date: Tue, 14 May 2024 06:10:26 +0100
Subject: [PATCH] Fix `Connection closed` error when using `usePresence` hook

Resolves #1753
---
 .../react-hooks/src/hooks/usePresence.ts      | 42 ++++++++++++-------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/src/platform/react-hooks/src/hooks/usePresence.ts b/src/platform/react-hooks/src/hooks/usePresence.ts
index a22d808ba..4e6a44e2c 100644
--- a/src/platform/react-hooks/src/hooks/usePresence.ts
+++ b/src/platform/react-hooks/src/hooks/usePresence.ts
@@ -1,9 +1,10 @@
 import type * as Ably from 'ably';
-import { useCallback, useEffect, useRef } from 'react';
+import { useCallback, useEffect, useRef, useState } from 'react';
 import { ChannelParameters } from '../AblyReactHooks.js';
 import { useAbly } from './useAbly.js';
 import { useChannelInstance } from './useChannelInstance.js';
 import { useStateErrors } from './useStateErrors.js';
+import { useConnectionStateListener } from './useConnectionStateListener.js';
 
 export interface PresenceResult<T> {
   updateStatus: (messageOrPresenceObject: T) => void;
@@ -26,6 +27,7 @@ export function usePresence<T = any>(
   const ably = useAbly(params.ablyId);
   const { channel } = useChannelInstance(params.ablyId, params.channelName);
   const { connectionError, channelError } = useStateErrors(params);
+
   // we can't simply add messageOrPresenceObject to dependency list in our useCallback/useEffect hooks,
   // since it will most likely cause an infinite loop of updates in cases when user calls this hook
   // with an object literal instead of a state or memoized object.
@@ -33,30 +35,40 @@ export function usePresence<T = any>(
   // note that it still prevents us from automatically re-entering presence with new messageOrPresenceObject if it changes.
   // one of the options to fix this, is to use deep equals to check if the object has actually changed. see https://github.com/ably/ably-js/issues/1688.
   const messageOrPresenceObjectRef = useRef(messageOrPresenceObject);
-
   useEffect(() => {
     messageOrPresenceObjectRef.current = messageOrPresenceObject;
   }, [messageOrPresenceObject]);
 
-  const onMount = useCallback(async () => {
-    await channel.presence.enter(messageOrPresenceObjectRef.current);
-  }, [channel.presence]);
-
-  const onUnmount = useCallback(() => {
-    // if connection is in one of inactive states, leave call will produce exception
-    if (channel.state === 'attached' && !INACTIVE_CONNECTION_STATES.includes(ably.connection.state)) {
-      channel.presence.leave();
-    }
-  }, [channel, ably.connection.state]);
+  // we need to listen for the current connection state in order to react to it.
+  // for example, we should enter presence when first connected, re-enter when reconnected,
+  // and be able to prevent entering presence when the connection is in an inactive state.
+  // all of that can be achieved by using the useConnectionStateListener hook.
+  const [connectionState, setConnectionState] = useState(ably.connection.state);
+  useConnectionStateListener((stateChange) => {
+    setConnectionState(stateChange.current);
+  });
+  const shouldNotEnterPresence = INACTIVE_CONNECTION_STATES.includes(connectionState) || skip;
 
   useEffect(() => {
-    if (skip) return;
+    if (shouldNotEnterPresence) {
+      return;
+    }
 
+    const onMount = async () => {
+      await channel.presence.enter(messageOrPresenceObjectRef.current);
+    };
     onMount();
+
     return () => {
-      onUnmount();
+      // here we use the ably.connection.state property, which upon this cleanup function call
+      // will have the current connection state for that connection, thanks to us accessing the Ably instance here by reference.
+      // if the connection is in one of the inactive states or the channel is not attached, a presence.leave call will produce an exception.
+      // so we only leave presence in other cases.
+      if (channel.state === 'attached' && !INACTIVE_CONNECTION_STATES.includes(ably.connection.state)) {
+        channel.presence.leave();
+      }
     };
-  }, [skip, onMount, onUnmount]);
+  }, [shouldNotEnterPresence, channel, ably.connection.state]);
 
   const updateStatus = useCallback(
     (messageOrPresenceObject: T) => {