Function createExamResults

api/src/utils/exam.ts:64–103

(userExam: UserExam, originalExam: Exam)

 * @returns An object of the exam results.
 */
export function createExamResults(userExam: UserExam, originalExam: Exam) {
  const { userExamQuestions, examTimeInSeconds } = userExam;
  const {
    questions: originalQuestions,
    numberOfQuestionsInExam,
    passingPercent
  } = originalExam;

  const numberOfCorrectAnswers = userExamQuestions.reduce(
    (count, userQuestion) => {
      const originalQuestion = originalQuestions.find(
        examQuestion => examQuestion.id === userQuestion.id
      );

      if (!originalQuestion) {
        throw new Error('An error occurred. Could not find exam question.');
      }

      const isCorrect = originalQuestion.correctAnswers.find(
        examAnswer => examAnswer.id === userQuestion.answer.id
      );
      return isCorrect ? count + 1 : count;
    },
    0
  );

  // Percent rounded to one decimal place
  const percent = (numberOfCorrectAnswers / numberOfQuestionsInExam) * 100;
  const percentCorrect = Math.round(percent * 10) / 10;
  const passed = percentCorrect >= passingPercent;

  return {
    numberOfCorrectAnswers,
    numberOfQuestionsInExam,
    percentCorrect,
    passingPercent,
    passed,
    examTimeInSeconds
  };
}