fix: emit MediaStateChange on RemoteStream.replaceTrack

src/media/remote-stream.spec.ts

@@ -1,5 +1,5 @@
 import { createMockedStream } from '../util/test-utils';
-import { RemoteStream } from './remote-stream';
+import { RemoteMediaState, RemoteStream, RemoteStreamEventNames } from './remote-stream';
 
 describe('RemoteStream', () => {
   const mockStream = createMockedStream();
@@ -63,6 +63,46 @@ describe('RemoteStream', () => {
       expect(addEventListenerSpy).toHaveBeenCalledWith('mute', expect.anything());
       expect(addEventListenerSpy).toHaveBeenCalledWith('unmute', expect.anything());
     });
+
+    it('should emit MediaStateChange event if new track is muted but old track is not', () => {
+      expect.assertions(2);
+
+      // Set old track to be unmuted.
+      Object.defineProperty(mockStream.getTracks()[0], 'muted', {
+        value: false,
+        configurable: true,
+      });
+
+      // Set new track to be muted.
+      const newTrack = new MediaStreamTrack();
+      Object.defineProperty(newTrack, 'muted', { value: true });
+
+      const emitSpy = jest.spyOn(remoteStream[RemoteStreamEventNames.MediaStateChange], 'emit');
+      remoteStream.replaceTrack(newTrack);
+
+      expect(emitSpy).toHaveBeenCalledTimes(1);
+      expect(emitSpy).toHaveBeenCalledWith(RemoteMediaState.Stopped);
+    });
+
+    it('should emit MediaStateChange event if old track is muted but new track is not', () => {
+      expect.assertions(2);
+
+      // Set old track to be muted.
+      Object.defineProperty(mockStream.getTracks()[0], 'muted', {
+        value: true,
+        configurable: true,
+      });
+
+      // Set new track to be unmuted.
+      const newTrack = new MediaStreamTrack();
+      Object.defineProperty(newTrack, 'muted', { value: false });
+
+      const emitSpy = jest.spyOn(remoteStream[RemoteStreamEventNames.MediaStateChange], 'emit');
+      remoteStream.replaceTrack(newTrack);
+
+      expect(emitSpy).toHaveBeenCalledTimes(1);
+      expect(emitSpy).toHaveBeenCalledWith(RemoteMediaState.Started);
+    });
   });
 
   describe('stop', () => {

src/media/remote-stream.ts

@@ -104,6 +104,14 @@ class _RemoteStream extends Stream {
     this.outputStream.addTrack(newTrack);
     this.addTrackHandlers(newTrack);
 
+    if (oldTrack.muted !== newTrack.muted) {
+      if (newTrack.muted) {
+        this.handleMediaStopped();
+      } else {
+        this.handleMediaStarted();
+      }
+    }
+
     // TODO: Chrome/React may not automatically refresh the media element with the new track when
     // the output track has changed, so we may need to emit an event here if this is the case.
     // this[StreamEventNames.OutputTrackChange].emit(newTrack);