review: extract ControlledAudioOutput in its own file

src/state/ControlledAudioOutput.ts

@@ -0,0 +1,132 @@
+/*
+Copyright 2026 Element Corp.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { logger as rootLogger } from "matrix-js-sdk/lib/logger";
+import { combineLatest, merge, startWith, Subject, tap } from "rxjs";
+
+import {
+  availableOutputDevices$ as controlledAvailableOutputDevices$,
+  outputDevice$ as controlledOutputSelection$,
+} from "../controls.ts";
+import type { Behavior } from "./Behavior.ts";
+import type { ObservableScope } from "./ObservableScope.ts";
+import {
+  type AudioOutputDeviceLabel,
+  availableRawDevices$,
+  iosDeviceMenu$,
+  type MediaDevice,
+  type SelectedAudioOutputDevice,
+} from "./MediaDevices.ts";
+
+// This hardcoded id is used in EX ios! It can only be changed in coordination with
+// the ios swift team.
+const EARPIECE_CONFIG_ID = "earpiece-id";
+
+/**
+ * A special implementation of audio output that allows the hosting application
+ * to have more control over the device selection process. This is used when the
+ * `controlledAudioDevices` URL parameter is set, which is currently only true on mobile.
+ */
+export class ControlledAudioOutput implements MediaDevice<
+  AudioOutputDeviceLabel,
+  SelectedAudioOutputDevice
+> {
+  private logger = rootLogger.getChild("[MediaDevices ControlledAudioOutput]");
+  // We need to subscribe to the raw devices so that the OS does update the input
+  // back to what it was before. otherwise we will switch back to the default
+  // whenever we allocate a new stream.
+  public readonly availableRaw$ = availableRawDevices$(
+    "audiooutput",
+    this.usingNames$,
+    this.scope,
+    this.logger,
+  );
+
+  public readonly available$ = this.scope.behavior(
+    combineLatest(
+      [controlledAvailableOutputDevices$.pipe(startWith([])), iosDeviceMenu$],
+      (availableRaw, iosDeviceMenu) => {
+        const available = new Map<string, AudioOutputDeviceLabel>(
+          availableRaw.map(
+            ({ id, name, isEarpiece, isSpeaker /*,isExternalHeadset*/ }) => {
+              let deviceLabel: AudioOutputDeviceLabel;
+              // if (isExternalHeadset) // Do we want this?
+              if (isEarpiece) deviceLabel = { type: "earpiece" };
+              else if (isSpeaker) deviceLabel = { type: "speaker" };
+              else deviceLabel = { type: "name", name };
+              return [id, deviceLabel];
+            },
+          ),
+        );
+
+        // Create a virtual earpiece device in case a non-earpiece device is
+        // designated for this purpose
+        if (iosDeviceMenu && availableRaw.some((d) => d.forEarpiece)) {
+          this.logger.info(
+            `IOS Add virtual earpiece device with id ${EARPIECE_CONFIG_ID}`,
+          );
+          available.set(EARPIECE_CONFIG_ID, { type: "earpiece" });
+        }
+
+        return available;
+      },
+    ),
+  );
+
+  private readonly deviceSelection$ = new Subject<string>();
+
+  public select(id: string): void {
+    this.logger.info(`select device: ${id}`);
+    this.deviceSelection$.next(id);
+  }
+
+  public readonly selected$ = this.scope.behavior(
+    combineLatest(
+      [
+        this.available$,
+        merge(
+          controlledOutputSelection$.pipe(startWith(undefined)),
+          this.deviceSelection$,
+        ),
+      ],
+      (available, preferredId) => {
+        const id = preferredId ?? available.keys().next().value;
+        return id === undefined
+          ? undefined
+          : { id, virtualEarpiece: id === EARPIECE_CONFIG_ID };
+      },
+    ).pipe(
+      tap((selected) => {
+        this.logger.debug(`selected device: ${selected?.id}`);
+      }),
+    ),
+  );
+
+  public constructor(
+    private readonly usingNames$: Behavior<boolean>,
+    private readonly scope: ObservableScope,
+  ) {
+    this.selected$.subscribe((device) => {
+      // Let the hosting application know which output device has been selected.
+      // This information is probably only of interest if the earpiece mode has
+      // been selected - for example, Element X iOS listens to this to determine
+      // whether it should enable the proximity sensor.
+      if (device !== undefined) {
+        this.logger.info("onAudioDeviceSelect called:", device);
+        window.controls.onAudioDeviceSelect?.(device.id);
+        // Also invoke the deprecated callback for backward compatibility
+        window.controls.onOutputDeviceSelect?.(device.id);
+      }
+    });
+    this.available$.subscribe((available) => {
+      this.logger.debug("available devices:", available);
+    });
+    this.availableRaw$.subscribe((availableRaw) => {
+      this.logger.debug("available raw devices:", availableRaw);
+    });
+  }
+}

src/state/MediaDevices.ts

@@ -9,37 +9,28 @@ import {
   combineLatest,
   filter,
   map,
-  merge,
+  type Observable,
   pairwise,
-  startWith,
   Subject,
   switchMap,
-  type Observable,
-  tap,
 } from "rxjs";
 import { createMediaDeviceObserver } from "@livekit/components-core";
 import { type Logger, logger as rootLogger } from "matrix-js-sdk/lib/logger";
 
 import {
+  alwaysShowIphoneEarpiece as alwaysShowIphoneEarpieceSetting,
   audioInput as audioInputSetting,
   audioOutput as audioOutputSetting,
   videoInput as videoInputSetting,
-  alwaysShowIphoneEarpiece as alwaysShowIphoneEarpieceSetting,
 } from "../settings/settings";
 import { type ObservableScope } from "./ObservableScope";
-import {
-  outputDevice$ as controlledOutputSelection$,
-  availableOutputDevices$ as controlledAvailableOutputDevices$,
-} from "../controls";
+import { availableOutputDevices$ as controlledAvailableOutputDevices$ } from "../controls";
 import { getUrlParams } from "../UrlParams";
 import { platform } from "../Platform";
 import { switchWhen } from "../utils/observable";
 import { type Behavior, constant } from "./Behavior";
 import { AndroidControlledAudioOutput } from "./AndroidControlledAudioOutput.ts";
-
-// This hardcoded id is used in EX ios! It can only be changed in coordination with
-// the ios swift team.
-const EARPIECE_CONFIG_ID = "earpiece-id";
+import { ControlledAudioOutput } from "./ControlledAudioOutput.ts";
 
 export type DeviceLabel =
   | { type: "name"; name: string }
@@ -127,7 +118,7 @@ export interface MediaDevice<Label, Selected> {
 export const iosDeviceMenu$ =
   platform === "ios" ? constant(true) : alwaysShowIphoneEarpieceSetting.value$;
 
-function availableRawDevices$(
+export function availableRawDevices$(
   kind: MediaDeviceKind,
   usingNames$: Behavior<boolean>,
   scope: ObservableScope,
@@ -175,9 +166,6 @@ function buildDeviceMap(
 function selectDevice$<Label>(
   available$: Observable<Map<string, Label>>,
   preferredId$: Observable<string | undefined>,
-  defaultPicker: (available: Map<string, Label>) => string | undefined = (
-    available,
-  ) => available.keys().next().value,
 ): Observable<string | undefined> {
   return combineLatest([available$, preferredId$], (available, preferredId) => {
     if (available.size) {
@@ -196,7 +184,7 @@ function selectDevice$<Label>(
         return preferredId;
       } else {
         // No preferred, so pick a default.
-        return defaultPicker(available);
+        return available.keys().next().value;
       }
     }
     return undefined;
@@ -319,111 +307,6 @@ export class AudioOutput implements MediaDevice<
   }
 }
 
-/**
- * A special implementation of audio output that allows the hosting application
- * to have more control over the device selection process. This is used when the
- * `controlledAudioDevices` URL parameter is set, which is currently only true on mobile.
- */
-class ControlledAudioOutput implements MediaDevice<
-  AudioOutputDeviceLabel,
-  SelectedAudioOutputDevice
-> {
-  private logger = rootLogger.getChild("[MediaDevices ControlledAudioOutput]");
-  // We need to subscribe to the raw devices so that the OS does update the input
-  // back to what it was before. otherwise we will switch back to the default
-  // whenever we allocate a new stream.
-  public readonly availableRaw$ = availableRawDevices$(
-    "audiooutput",
-    this.usingNames$,
-    this.scope,
-    this.logger,
-  );
-
-  public readonly available$ = this.scope.behavior(
-    combineLatest(
-      [controlledAvailableOutputDevices$.pipe(startWith([])), iosDeviceMenu$],
-      (availableRaw, iosDeviceMenu) => {
-        const available = new Map<string, AudioOutputDeviceLabel>(
-          availableRaw.map(
-            ({ id, name, isEarpiece, isSpeaker /*,isExternalHeadset*/ }) => {
-              let deviceLabel: AudioOutputDeviceLabel;
-              // if (isExternalHeadset) // Do we want this?
-              if (isEarpiece) deviceLabel = { type: "earpiece" };
-              else if (isSpeaker) deviceLabel = { type: "speaker" };
-              else deviceLabel = { type: "name", name };
-              return [id, deviceLabel];
-            },
-          ),
-        );
-
-        // Create a virtual earpiece device in case a non-earpiece device is
-        // designated for this purpose
-        if (iosDeviceMenu && availableRaw.some((d) => d.forEarpiece)) {
-          this.logger.info(
-            `IOS Add virtual earpiece device with id ${EARPIECE_CONFIG_ID}`,
-          );
-          available.set(EARPIECE_CONFIG_ID, { type: "earpiece" });
-        }
-
-        return available;
-      },
-    ),
-  );
-
-  private readonly deviceSelection$ = new Subject<string>();
-
-  public select(id: string): void {
-    this.logger.info(`select device: ${id}`);
-    this.deviceSelection$.next(id);
-  }
-
-  public readonly selected$ = this.scope.behavior(
-    combineLatest(
-      [
-        this.available$,
-        merge(
-          controlledOutputSelection$.pipe(startWith(undefined)),
-          this.deviceSelection$,
-        ),
-      ],
-      (available, preferredId) => {
-        const id = preferredId ?? available.keys().next().value;
-        return id === undefined
-          ? undefined
-          : { id, virtualEarpiece: id === EARPIECE_CONFIG_ID };
-      },
-    ).pipe(
-      tap((selected) => {
-        this.logger.debug(`selected device: ${selected?.id}`);
-      }),
-    ),
-  );
-
-  public constructor(
-    private readonly usingNames$: Behavior<boolean>,
-    private readonly scope: ObservableScope,
-  ) {
-    this.selected$.subscribe((device) => {
-      // Let the hosting application know which output device has been selected.
-      // This information is probably only of interest if the earpiece mode has
-      // been selected - for example, Element X iOS listens to this to determine
-      // whether it should enable the proximity sensor.
-      if (device !== undefined) {
-        this.logger.info("onAudioDeviceSelect called:", device);
-        window.controls.onAudioDeviceSelect?.(device.id);
-        // Also invoke the deprecated callback for backward compatibility
-        window.controls.onOutputDeviceSelect?.(device.id);
-      }
-    });
-    this.available$.subscribe((available) => {
-      this.logger.debug("available devices:", available);
-    });
-    this.availableRaw$.subscribe((availableRaw) => {
-      this.logger.debug("available raw devices:", availableRaw);
-    });
-  }
-}
-
 class VideoInput implements MediaDevice<DeviceLabel, SelectedDevice> {
   private logger = rootLogger.getChild("[MediaDevices VideoInput]");