Close viewer after viewing a single story

ts/state/ducks/stories.ts

@@ -842,6 +842,15 @@ const viewStory: ViewStoryActionCreatorType = (
       return;
     }
 
+    if (storyViewMode === StoryViewModeType.Single) {
+      // Close the viewer we were just looking at a single story.
+      dispatch({
+        type: VIEW_STORY,
+        payload: undefined,
+      });
+      return;
+    }
+
     // When paging through all sent stories
     // Note the order is reversed[1][2] here because we sort the stories by
     // recency in descending order but the story viewer plays them in

ts/test-electron/state/ducks/stories_test.ts

@@ -130,6 +130,21 @@ describe('both/state/ducks/stories', () => {
       });
     });
 
+    it('closes the viewer when viewing a single story', () => {
+      const dispatch = sinon.spy();
+
+      viewStory({
+        storyId: UUID.generate().toString(),
+        storyViewMode: StoryViewModeType.Single,
+        viewDirection: StoryViewDirectionType.Next,
+      })(dispatch, getEmptyRootState, null);
+
+      sinon.assert.calledWith(dispatch, {
+        type: 'stories/VIEW_STORY',
+        payload: undefined,
+      });
+    });
+
     it('does not find a story', () => {
       const dispatch = sinon.spy();
       viewStory({