From 8e19f8012b7dae49fcf71d73b9bbbfc26adeef89 Mon Sep 17 00:00:00 2001
From: Aniket-Engg <aniketengg.225@gmail.com>
Date: Thu, 20 Apr 2023 19:06:35 +0530
Subject: [PATCH] off the event

---
 apps/etherscan/src/app/views/VerifyView.tsx | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/apps/etherscan/src/app/views/VerifyView.tsx b/apps/etherscan/src/app/views/VerifyView.tsx
index 902a12b9bc..aa90d28aa7 100644
--- a/apps/etherscan/src/app/views/VerifyView.tsx
+++ b/apps/etherscan/src/app/views/VerifyView.tsx
@@ -1,4 +1,4 @@
-import React, { useRef, useState } from "react"
+import React, { useEffect, useRef, useState } from "react"
 
 import {
   PluginClient,
@@ -34,6 +34,18 @@ export const VerifyView: React.FC<Props> = ({
   const [showConstructorArgs, setShowConstructorArgs] = useState(false)
   const verificationResult = useRef({})
 
+  useEffect(() => {
+    if (client && client.on) {
+      client.on("blockchain" as any, 'networkStatus', (result) => {
+        setNetworkName(result.network.name)
+      })
+    }
+    return () => {
+      // To fix memory leak
+      if (client && client.off) client.off("blockchain" as any, 'networkStatus')
+    }
+  }, [client])
+
   const onVerifyContract = async (values: FormValues) => {
     const compilationResult = (await client.call(
       "solidity",
@@ -83,11 +95,6 @@ export const VerifyView: React.FC<Props> = ({
         onSubmit={(values) => onVerifyContract(values)}
       >
         {({ errors, touched, handleSubmit, handleChange, isSubmitting }) => {
-          if (client && client.on) {
-            client.on("blockchain" as any, 'networkStatus', (result) => {
-              setNetworkName(result.network.name)
-            })
-          }
           return (<form onSubmit={handleSubmit}>
             <div className="form-group">
               <label htmlFor="network">Selected Network</label>