How to Build a OSU GPA Calculator

const OSU_GRADE_POINTS = {
  'A':  4.0, 'A-': 3.7,
  'B+': 3.3, 'B':  3.0, 'B-': 2.7,
  'C+': 2.3, 'C':  2.0, 'C-': 1.7,
  'D+': 1.3, 'D':  1.0,
  'E':  0.0  // OSU uses E instead of F
  };

  const EXCLUDED_GRADES = ['EN', 'S', 'U', 'I', 'W', 'PA', 'NP'];

  function calculateOSUGPA(courses) {
  let totalPoints = 0;
  let totalCredits = 0;

  for (const course of courses) {
    if (EXCLUDED_GRADES.includes(course.grade)) continue;

    const points = OSU_GRADE_POINTS[course.grade];
    if (points === undefined) continue;

    totalPoints += points * course.creditHours;
    totalCredits += course.creditHours;
  }

  return totalCredits > 0
    ? Math.round((totalPoints / totalCredits) * 1000) / 1000
    : 0;
  }

  function calculateCumulativeGPA(currentGPA, currentHours, newCourses) {
  const termGPA = calculateOSUGPA(newCourses);
  const termHours = newCourses
    .filter(c => !EXCLUDED_GRADES.includes(c.grade))
    .reduce((sum, c) => sum + c.creditHours, 0);

  const totalPoints = (currentGPA * currentHours) + (termGPA * termHours);
  const totalHours = currentHours + termHours;

  return totalHours > 0
    ? Math.round((totalPoints / totalHours) * 1000) / 1000
    : 0;
  }

  function getHonorsStatus(cumulativeGPA) {
  if (cumulativeGPA >= 3.9) return 'Summa Cum Laude';
  if (cumulativeGPA >= 3.7) return 'Magna Cum Laude';
  if (cumulativeGPA >= 3.5) return 'Cum Laude';
  return null;
  }