Merge pull request #1550 from mchangrh/stricter-ts

add noFallThrough, inplicitReturn, update packages

src/js-components/previewBar.ts

@@ -744,7 +744,7 @@ class PreviewBar {
                 chaptersContainer.style.display = "none";
             }
 
-            return;
+            return [];
         }
 
         segments ??= [];