Add LocalTrackSubscribed engine event (#1222)

* Add LocalTrackSubscribed engine event

* Create sixty-foxes-refuse.md

.changeset/sixty-foxes-refuse.md

@@ -0,0 +1,5 @@
+---
+"livekit-client": patch
+---
+
+Add internal LocalTrackSubscribed engine event

src/api/SignalClient.ts

@@ -144,6 +144,8 @@ export class SignalClient {
 
   onRequestResponse?: (response: RequestResponse) => void;
 
+  onLocalTrackSubscribed?: (trackSid: string) => void;
+
   connectOptions?: ConnectOpts;
 
   ws?: WebSocket;
@@ -743,6 +745,10 @@ export class SignalClient {
       if (this.onRequestResponse) {
         this.onRequestResponse(msg.value);
       }
+    } else if (msg.case === 'trackSubscribed') {
+      if (this.onLocalTrackSubscribed) {
+        this.onLocalTrackSubscribed(msg.value.trackSid);
+      }
     } else {
       this.log.debug('unsupported message', { ...this.logContext, msgCase: msg.case });
     }

src/room/RTCEngine.ts

@@ -494,6 +494,10 @@ export default class RTCEngine extends (EventEmitter as new () => TypedEventEmit
       this.emit(EngineEvent.LocalTrackUnpublished, response);
     };
 
+    this.client.onLocalTrackSubscribed = (trackSid: string) => {
+      this.emit(EngineEvent.LocalTrackSubscribed, trackSid);
+    };
+
     this.client.onTokenRefresh = (token: string) => {
       this.token = token;
     };
@@ -1413,6 +1417,7 @@ export type EngineEventCallbacks = {
   subscriptionPermissionUpdate: (update: SubscriptionPermissionUpdate) => void;
   subscribedQualityUpdate: (update: SubscribedQualityUpdate) => void;
   localTrackUnpublished: (unpublishedResponse: TrackUnpublishedResponse) => void;
+  localTrackSubscribed: (trackSid: string) => void;
   remoteMute: (trackSid: string, muted: boolean) => void;
   offline: () => void;
   signalRequestResponse: (response: RequestResponse) => void;

src/room/events.ts

@@ -538,6 +538,7 @@ export enum EngineEvent {
   RemoteMute = 'remoteMute',
   SubscribedQualityUpdate = 'subscribedQualityUpdate',
   LocalTrackUnpublished = 'localTrackUnpublished',
+  LocalTrackSubscribed = 'localTrackSubscribed',
   Offline = 'offline',
   SignalRequestResponse = 'signalRequestResponse',
 }