Negative Marking Form Extension

negative-marking-form-extension.gs

/**
 * Negative Marking Forms Extension
 * Created by Vedant K <github.com/gamemaker1>
 * ISC License • Copyright Vedant K 2022
 * 
 * This extension allows you to add negative marking to a quiz in Google Forms.
 * 
 * The settings are as follows:
 * - Single Correct Questions (SCQs) = -1 [upon wrong answer]
 * - Multiple Correct Questions (MCQs) = -2 [upon wrong answer, no partial marking]
 * - Integer Type Questions = NaN [no negative marking]
 * 
 * It is not possible at the time to change the score of Matrix type questions
 * (https://issuetracker.google.com/issues/142531514#comment7), so negative marking
 * on those questions will not be done.
 **/

const ADDON_TITLE = 'Negative Marking Extension';

const onInstall = onOpen
const onOpen = () => {
  const form = FormApp.getActiveForm();
  const triggers = ScriptApp.getUserTriggers(form);
  
  // Create a new trigger only if required.
  let existingTrigger = undefined;
  for (const trigger of triggers) {
    if (trigger.getEventType() === ScriptApp.EventType.ON_FORM_SUBMIT) {
      existingTrigger = trigger;
      break;
    }
  }
  if (!existingTrigger) {
    ScriptApp.newTrigger('applyNegativeMarking')
      .forForm(form)
      .onFormSubmit()
      .create();
  }
}

const applyNegativeMarking = () => {
  // Open the form in question.
  const form = FormApp.getActiveForm()

  // Retrieve all the questions and responses.
  const responses = form.getResponses()
  const questions = form.getItems()
  
  // Go through each form response.
  for (const response of responses) {
    // Go through each question for each response.
    for (const question of questions) {
      // Fetch the response the user gave for the question in question.
      const answer = response.getGradableResponseForItem(question)
      if (!answer) continue

      // If the response is blank, the answer is correct, or the score has already been
      // modified, let the score be as is.
      if (!answer.getResponse() ||
        (question.getType() !== FormApp.ItemType.CHECKBOX_GRID && answer.getScore() !== 0)
      ) continue

      // Apply negative marking as per the type of question.
      if (question.getType() === FormApp.ItemType.MULTIPLE_CHOICE) {
        answer.setScore(-1)
        response.withItemGrade(answer)
        
        continue
      } else if (question.getType() === FormApp.ItemType.CHECKBOX) {
        answer.setScore(-2)
        response.withItemGrade(answer)
        
        continue
      } else if (question.getType() === FormApp.ItemType.TEXT) {
        answer.setScore(0)
        response.withItemGrade(answer)
        
        continue
      } else {}
    }
  }
  
  // Upload the new scores.
  form.submitGrades(responses)
}