fix(websockets): run handle connection hook once nestjs#3704

Author: kamilmysliwiec

packages/websockets/utils/compare-element.util.ts

@@ -0,0 +1,7 @@
+export function compareElementAt(
+  prev: unknown[],
+  curr: unknown[],
+  index: number,
+) {
+  return prev && curr && prev[index] === curr[index];
+}

packages/websockets/web-sockets-controller.ts

@@ -14,6 +14,7 @@ import {
 import { NestGateway } from './interfaces/nest-gateway.interface';
 import { SocketEventsHost } from './interfaces/socket-events-host.interface';
 import { SocketServerProvider } from './socket-server-provider';
+import { compareElementAt } from './utils/compare-element.util';
 
 export class WebSocketsController {
   private readonly metadataExplorer = new GatewayMetadataExplorer(
@@ -119,7 +120,9 @@ export class WebSocketsController {
   public subscribeConnectionEvent(instance: NestGateway, event: Subject<any>) {
     if (instance.handleConnection) {
       event
-        .pipe(distinctUntilChanged())
+        .pipe(
+          distinctUntilChanged((prev, curr) => compareElementAt(prev, curr, 0)),
+        )
         .subscribe((args: any[]) => instance.handleConnection(...args));
     }
   }