From 4e7f75868fb0ae4f8a197268c3d6e483ff542f16 Mon Sep 17 00:00:00 2001
From: Franck Royer <franck@status.im>
Date: Wed, 16 Jun 2021 16:36:12 +1000
Subject: [PATCH] Clean up observer when component dismount

---
 examples/eth-dm/src/App.tsx | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/examples/eth-dm/src/App.tsx b/examples/eth-dm/src/App.tsx
index 67be5f1436..830cd010d5 100644
--- a/examples/eth-dm/src/App.tsx
+++ b/examples/eth-dm/src/App.tsx
@@ -72,6 +72,11 @@ function App() {
   useEffect(() => {
     if (!waku) return;
     waku.relay.addObserver(observerPublicKeyMessage, [PublicKeyContentTopic]);
+
+    return function cleanUp() {
+      if (!waku) return;
+      waku.relay.deleteObserver(observerPublicKeyMessage, [PublicKeyContentTopic]);
+    }
   });
 
   useEffect(() => {
@@ -81,6 +86,16 @@ function App() {
       observerDirectMessage.bind({}, ethDmKeyPair.privateKey),
       [DirectMessageContentTopic]
     );
+
+    return function cleanUp() {
+      if (!waku) return;
+      if (!ethDmKeyPair) return;
+      waku.relay.deleteObserver(
+        observerDirectMessage.bind({}, ethDmKeyPair.privateKey),
+        [DirectMessageContentTopic]
+      );
+
+    }
   });
 
   const broadcastPublicKey = () => {
@@ -109,6 +124,8 @@ function App() {
   };
 
   const sendDummyMessage = () => {
+    if (!waku) return;
+
     console.log(`Sending messages to ${publicKeys.size} peers`);
     publicKeys.forEach(async (publicKey, address) => {
       const msg = await encodeEncryptedWakuMessage(