[+] Create method to calculate GPA

src/utils/gpa-utils.ts

@@ -1,6 +1,8 @@
 /**
  * This is an utility class to calculate GPA.
  */
+import {Course} from '@/components/app/app';
+
 export class GPAUtils
 {
     // [[Min score, Letter grade, Base GPA], ...]
@@ -23,4 +25,49 @@ export class GPAUtils
     public static MIN = 0;
     public static LETTER = 1;
     public static GPA = 2;
+
+    /**
+     * Calculate GPA for a list of couses
+     *
+     * @param coursesOriginal List of courses
+     */
+    public static gpa(coursesOriginal: Course[]): number
+    {
+        // Clone array
+        let courses: Course[] = [];
+
+        // Remove all courses that does not have a grade
+        coursesOriginal.forEach(course =>
+        {
+            if (course.numericGrade != null)
+            {
+                courses.push(course);
+            }
+        });
+
+        // If no course have grade, return -1
+        if (courses.length == 0)
+        {
+            return -1;
+        }
+
+        // Count total GPA
+        let totalGPA = 0;
+        courses.forEach(course =>
+        {
+            // Find the GPA for this course. TODO: Remove course that does not have level
+            this.SCALE.forEach(scale =>
+            {
+                // Letter grades are the same
+                if (scale[this.LETTER] == course.letterGrade)
+                {
+                    totalGPA += <number> scale[this.GPA] + course.scaleUp;
+                    return;
+                }
+            })
+        });
+
+        // Get average GPA
+        return totalGPA / courses.length;
+    }
 }