From 647b997fc07bfa4650bd38caf86249044be41f9a Mon Sep 17 00:00:00 2001
From: Douglas Armstrong <dougarmstrong@fb.com>
Date: Mon, 25 May 2020 17:17:37 -0700
Subject: [PATCH] [docs] Fix bi-directional syncing example

---
 docs/docs/guides/asynchronous-state-sync.md | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/docs/docs/guides/asynchronous-state-sync.md b/docs/docs/guides/asynchronous-state-sync.md
index bf8a43ec..66c5cd0b 100644
--- a/docs/docs/guides/asynchronous-state-sync.md
+++ b/docs/docs/guides/asynchronous-state-sync.md
@@ -23,7 +23,7 @@ function CurrentUserInfo() {
 
 ## Sync State From Server
 
-We can subscribe to asynchronous changes in the remote state and update the atom value to match.  This can be done using standard React `useEffect()` hook or other popular libraries.
+We can subscribe to asynchronous changes in the remote state and update the atom value to match.  This can be done using standard React [`useEffect()`]() hook or other popular libraries.
 
 ```jsx
 function CurrentUserIDSubscription() {
@@ -59,12 +59,12 @@ You can also sync the state so local changes are updated on the server:
 ```jsx
 function CurrentUserIDSubscription() {
   const [currentUserID, setCurrentUserID] = useRecoilState(currentUserIDState);
-  let knownServerCurrentUserID;
+  const knownServerCurrentUserID = useRef(currentUserID);
 
   // Subscribe server changes to update atom state
   useEffect(() => {
     function handleUserChange(id) {
-      knownServerCurrentUserID = id;
+      knownServerCurrentUserID.current = id;
       setCurrentUserID(id);
     }
 
@@ -73,15 +73,15 @@ function CurrentUserIDSubscription() {
     return function cleanup() {
       RemoteServerAPI.unsubscribeFromFriendStatus(handleUserChange);
     };
-  }, []);
+  }, [knownServerCurrentUserID]);
 
   // Subscribe atom changes to update server state
   useEffect(() => {
-    if (currentUserID !== knownServerCurrentUserID) {
-      knownServerCurrentID = currentUserID;
+    if (currentUserID !== knownServerCurrentUserID.current) {
+      knownServerCurrentID.current = currentUserID;
       RemoteServerAPI.updateCurrentUser(currentUserID);
     }
-  }, [currentUserID, knownServerCurrentUserID]);
+  }, [currentUserID, knownServerCurrentUserID.current]);
 
   return null;
 }