Update generate-playlist.js

scripts/store/getters/group_title.js

@@ -1,3 +1,12 @@
 module.exports = function () {
-  return this.group_title || 'Undefined'
+  if (this.group_title) return this.group_title
+
+  if (this.categories.length) {
+    return this.categories
+      .map(category => category.name)
+      .sort()
+      .join(';')
+  }
+
+  return 'Undefined'
 }