From 2cbfc49a2b089dbd96d0b52e9273527379f044a9 Mon Sep 17 00:00:00 2001
From: Max Goodhart <c@chromakode.com>
Date: Sun, 5 Jul 2020 22:56:00 -0700
Subject: [PATCH] Prevent control page echoing back CRDT updates

---
 src/web/control.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/web/control.js b/src/web/control.js
index c53a5c6..30dfb7a 100644
--- a/src/web/control.js
+++ b/src/web/control.js
@@ -144,14 +144,17 @@ function useStreamwallConnection(wsEndpoint) {
   }, [])
 
   useEffect(() => {
-    function sendUpdate(update) {
+    function sendUpdate(update, origin) {
+      if (origin === 'server') {
+        return
+      }
       wsRef.current.send(update)
     }
     function receiveUpdate(ev) {
       if (!(ev.data instanceof ArrayBuffer)) {
         return
       }
-      Y.applyUpdate(stateDoc, new Uint8Array(ev.data))
+      Y.applyUpdate(stateDoc, new Uint8Array(ev.data), 'server')
     }
     stateDoc.on('update', sendUpdate)
     wsRef.current.addEventListener('message', receiveUpdate)