fix(core): derive effective mute state for volume UI components (#753)

packages/core/src/core/ui/mute-button/mute-button-core.ts

@@ -68,7 +68,7 @@ export class MuteButtonCore {
   getState(): MuteButtonState {
     const media = this.#media!;
     return {
-      muted: media.muted,
+      muted: media.muted || media.volume === 0,
       volumeLevel: getVolumeLevel(media),
     };
   }

packages/core/src/core/ui/mute-button/tests/mute-button-core.test.ts

@@ -50,6 +50,15 @@ describe('MuteButtonCore', () => {
       expect(core.getState().volumeLevel).toBe('off');
     });
 
+    it('derives muted as true when volume is 0 and not muted', () => {
+      const core = new MuteButtonCore();
+      core.setMedia(createMediaState({ volume: 0, muted: false }));
+      const state = core.getState();
+
+      expect(state.muted).toBe(true);
+      expect(state.volumeLevel).toBe('off');
+    });
+
     it('returns low when volume < 0.5', () => {
       const core = new MuteButtonCore();
       core.setMedia(createMediaState({ volume: 0.3 }));

packages/core/src/core/ui/volume-slider/tests/volume-slider-core.test.ts

@@ -105,6 +105,16 @@ describe('VolumeSliderCore', () => {
 
       expect(state.muted).toBe(false);
     });
+
+    it('derives muted as true when volume is 0 and not muted', () => {
+      const core = new VolumeSliderCore();
+      core.setInput(createInput());
+      core.setMedia(createMediaState({ volume: 0, muted: false }));
+      const state = core.getState();
+
+      expect(state.muted).toBe(true);
+      expect(state.fillPercent).toBe(0);
+    });
   });
 
   describe('getAttrs', () => {
@@ -150,14 +160,14 @@ describe('VolumeSliderCore', () => {
       expect(attrs['aria-label']).toBe('Audio');
     });
 
-    it('shows 0 percent when volume is 0', () => {
+    it('shows 0 percent muted when volume is 0', () => {
       const core = new VolumeSliderCore();
       core.setInput(createInput());
       core.setMedia(createMediaState({ volume: 0 }));
       const state = core.getState();
       const attrs = core.getAttrs(state);
 
-      expect(attrs['aria-valuetext']).toBe('0 percent');
+      expect(attrs['aria-valuetext']).toBe('0 percent, muted');
     });
   });
 

packages/core/src/core/ui/volume-slider/volume-slider-core.ts

@@ -40,6 +40,7 @@ export class VolumeSliderCore extends SliderCore {
   getState(): VolumeSliderState {
     const media = this.#media!;
     const { volume, muted } = media;
+    const effectivelyMuted = muted || volume === 0;
     const { dragging, dragPercent } = this.input;
     const volumePercent = volume * 100;
     const value = dragging ? this.valueFromPercent(dragPercent) : volumePercent;
@@ -47,9 +48,9 @@ export class VolumeSliderCore extends SliderCore {
 
     return {
       ...base,
-      fillPercent: muted ? 0 : base.fillPercent,
+      fillPercent: effectivelyMuted ? 0 : base.fillPercent,
       volume,
-      muted,
+      muted: effectivelyMuted,
     };
   }
 

packages/core/src/dom/store/features/tests/volume.test.ts

@@ -114,25 +114,27 @@ describe('volumeFeature', () => {
     });
 
     describe('toggleMuted', () => {
-      it('toggles mute from false to true', async () => {
+      it('mutes when unmuted with volume > 0', async () => {
-        const video = createMockVideo({ muted: false });
+        const video = createMockVideo({ muted: false, volume: 0.8 });
         const store = createStore<PlayerTarget>()(volumeFeature);
         store.attach({ media: video, container: null });
 
         const result = await store.toggleMuted();
 
         expect(video.muted).toBe(true);
+        expect(video.volume).toBe(0.8);
         expect(result).toBe(true);
       });
 
-      it('toggles mute from true to false', async () => {
+      it('unmutes when muted with volume > 0', async () => {
-        const video = createMockVideo({ muted: true });
+        const video = createMockVideo({ muted: true, volume: 0.6 });
         const store = createStore<PlayerTarget>()(volumeFeature);
         store.attach({ media: video, container: null });
 
         const result = await store.toggleMuted();
 
         expect(video.muted).toBe(false);
+        expect(video.volume).toBe(0.6);
         expect(result).toBe(false);
       });
 
@@ -147,26 +149,16 @@ describe('volumeFeature', () => {
         expect(video.volume).toBe(0.25);
       });
 
-      it('preserves volume when unmuting with volume > 0', async () => {
+      it('unmutes and restores volume when volume is 0 and not muted', async () => {
-        const video = createMockVideo({ muted: true, volume: 0.6 });
+        const video = createMockVideo({ muted: false, volume: 0 });
         const store = createStore<PlayerTarget>()(volumeFeature);
         store.attach({ media: video, container: null });
 
-        await store.toggleMuted();
+        const result = await store.toggleMuted();
 
         expect(video.muted).toBe(false);
-        expect(video.volume).toBe(0.6);
+        expect(video.volume).toBe(0.25);
-      });
+        expect(result).toBe(false);
-
-      it('does not change volume when muting', async () => {
-        const video = createMockVideo({ muted: false, volume: 0.8 });
-        const store = createStore<PlayerTarget>()(volumeFeature);
-        store.attach({ media: video, container: null });
-
-        await store.toggleMuted();
-
-        expect(video.muted).toBe(true);
-        expect(video.volume).toBe(0.8);
       });
     });
   });

packages/core/src/dom/store/features/volume.ts

@@ -28,12 +28,14 @@ export const volumeFeature = definePlayerFeature({
 
     toggleMuted() {
       const { media } = target();
-      const willUnmute = media.muted;
+      const effectivelyMuted = media.muted || media.volume === 0;
-      media.muted = !media.muted;
 
-      // Restore a sensible volume when unmuting at zero.
+      if (effectivelyMuted) {
-      if (willUnmute && media.volume === 0) {
+        media.muted = false;
-        media.volume = UNMUTE_VOLUME;
+        // Restore a sensible volume when unmuting at zero.
+        if (media.volume === 0) media.volume = UNMUTE_VOLUME;
+      } else {
+        media.muted = true;
       }
 
       return media.muted;