[+] Encapsulate getGradingPeriods()

src/logic/course.ts

@@ -162,6 +162,15 @@ export default class Course
         return true;
     }
 
+    /**
+     * Get currently selected grading periods
+     */
+    get gradingPeriods(): number[]
+    {
+        let timeCode = Navigation.instance.getSelectedGradingPeriod();
+        return timeCode == -1 ? [0, 1, 2, 3] : [timeCode];
+    }
+
     /**
      * Get assignments of the selected time
      */