feat: Make cameras optional (#2343)

src/utils/substream.ts

@@ -1,18 +1,31 @@
 import { View } from '../view/view';
 
-export const getStreamCameraID = (view: View, cameraID?: string): string => {
-  return (
-    view.context?.live?.overrides?.get(cameraID ?? view.camera) ??
-    cameraID ??
-    view.camera
-  );
+/**
+ * Get the effective camera ID for streaming, considering substream overrides.
+ * Returns null if the view has no camera.
+ */
+export const getStreamCameraID = (
+  view: View,
+  cameraID?: string | null,
+): string | null => {
+  const baseCameraID = cameraID ?? view.camera;
+  if (!baseCameraID) {
+    return null;
+  }
+  return view.context?.live?.overrides?.get(baseCameraID) ?? baseCameraID;
 };
 
 export const hasSubstream = (view: View): boolean => {
+  if (!view.camera) {
+    return false;
+  }
   return getStreamCameraID(view) !== view.camera;
 };
 
 export const setSubstream = (view: View, substreamID: string): void => {
+  if (!view.camera) {
+    return;
+  }
   const overrides: Map<string, string> = view.context?.live?.overrides ?? new Map();
   overrides.set(view.camera, substreamID);
   view.mergeInContext({
@@ -21,6 +34,9 @@ export const setSubstream = (view: View, substreamID: string): void => {
 };
 
 export const removeSubstream = (view: View): void => {
+  if (!view.camera) {
+    return;
+  }
   const overrides: Map<string, string> | undefined = view.context?.live?.overrides;
   if (overrides && overrides.has(view.camera)) {
     view.context?.live?.overrides?.delete(view.camera);