From 0949fc076ef750af90f7d48fb0a96664b3877911 Mon Sep 17 00:00:00 2001
From: Tanmay Sharma <sharmatanmay617@gmail.com>
Date: Wed, 3 Dec 2025 06:23:19 +0530
Subject: [PATCH 1/2] fix(realtime): terminate web worker on disconnect to
 prevent memory leak

Web Workers were created in _startWorkerHeartbeat() but never terminated
in _teardownConnection(), causing memory accumulation with each
disconnect/reconnect cycle.

This fix adds a _terminateWorker() private method that properly terminates
the Web Worker and clears the reference, then calls it during connection
teardown.

Fixes #1902
---
 .../core/realtime-js/src/RealtimeClient.ts    | 13 ++++++++++
 .../test/RealtimeClient.worker.test.ts        | 24 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/packages/core/realtime-js/src/RealtimeClient.ts b/packages/core/realtime-js/src/RealtimeClient.ts
index 19db54fa6..40dc75e98 100755
--- a/packages/core/realtime-js/src/RealtimeClient.ts
+++ b/packages/core/realtime-js/src/RealtimeClient.ts
@@ -645,6 +645,7 @@ export default class RealtimeClient {
       this.conn = null
     }
     this._clearAllTimers()
+    this._terminateWorker()
     this.channels.forEach((channel) => channel.teardown())
   }
 
@@ -710,6 +711,18 @@ export default class RealtimeClient {
       interval: this.heartbeatIntervalMs,
     })
   }
+
+  /**
+   * Terminate the Web Worker and clear the reference
+   * @internal
+   */
+  private _terminateWorker(): void {
+    if (this.workerRef) {
+      this.log('worker', 'terminating worker')
+      this.workerRef.terminate()
+      this.workerRef = undefined
+    }
+  }
   /** @internal */
   private _onConnClose(event: any) {
     this._setConnectionState('disconnected')
diff --git a/packages/core/realtime-js/test/RealtimeClient.worker.test.ts b/packages/core/realtime-js/test/RealtimeClient.worker.test.ts
index 0c0bd644c..b159326c5 100644
--- a/packages/core/realtime-js/test/RealtimeClient.worker.test.ts
+++ b/packages/core/realtime-js/test/RealtimeClient.worker.test.ts
@@ -98,3 +98,27 @@ test('creates worker with blob URL when no workerUrl provided', () => {
     global.URL.createObjectURL = originalCreateObjectURL
   }
 })
+
+test('terminates worker on disconnect', () => {
+  // Establish connection first
+  client.connect()
+
+  // Trigger worker creation
+  client._onConnOpen()
+
+  // Verify worker was created
+  assert.ok(client.workerRef)
+  const worker = client.workerRef
+
+  // Spy on worker terminate method
+  const terminateSpy = vi.spyOn(worker, 'terminate')
+
+  // Disconnect the client
+  client.disconnect()
+
+  // Verify worker was terminated
+  expect(terminateSpy).toHaveBeenCalled()
+
+  // Verify workerRef was cleared
+  assert.equal(client.workerRef, undefined)
+})

From 6f6fec53ad2bf426c06905b3583c618869f6a84b Mon Sep 17 00:00:00 2001
From: Tanmay Sharma <tanmaysharma2123@gmail.com>
Date: Wed, 3 Dec 2025 20:34:27 +0530
Subject: [PATCH 2/2] fix(realtime): updated the worker clearance in the
 _startWorkerHeartBeat function

Previously, the worker error handler in _startWorkerHeartbeat() directly calledworkerRef.terminate()
without clearing the workerRef reference. This caused amemory leak on worker errors because on
reconnection, the guard check for workerRef would prevent creating a new worker, leaving the
connection withouta heartbeat mechanism.Now uses the centralized _terminateWorker() method which
both terminates theworker and clears the reference, ensuring proper cleanup and allowing newworkers
to be created on reconnection.This complements the fix in _teardownConnection() to fully prevent
workermemory leaks across all disconnect/error scenarios.
---
 packages/core/realtime-js/src/RealtimeClient.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/core/realtime-js/src/RealtimeClient.ts b/packages/core/realtime-js/src/RealtimeClient.ts
index 40dc75e98..94794d4b2 100755
--- a/packages/core/realtime-js/src/RealtimeClient.ts
+++ b/packages/core/realtime-js/src/RealtimeClient.ts
@@ -699,7 +699,7 @@ export default class RealtimeClient {
     this.workerRef = new Worker(objectUrl)
     this.workerRef.onerror = (error) => {
       this.log('worker', 'worker error', (error as ErrorEvent).message)
-      this.workerRef!.terminate()
+      this._terminateWorker()
     }
     this.workerRef.onmessage = (event) => {
       if (event.data.event === 'keepAlive') {