From dd7fe84ffdf89780cf1476e2697d2d5ed3e82222 Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gregor.kleen@ifi.lmu.de>
Date: Sat, 8 Feb 2020 01:08:03 +0100
Subject: [PATCH] fix(exam-correct): fix usage for non-lecturer

---
 .../src/utils/exam-correct/exam-correct.js    | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/frontend/src/utils/exam-correct/exam-correct.js b/frontend/src/utils/exam-correct/exam-correct.js
index a7337c9eb..3daab9761 100644
--- a/frontend/src/utils/exam-correct/exam-correct.js
+++ b/frontend/src/utils/exam-correct/exam-correct.js
@@ -78,8 +78,10 @@ export class ExamCorrect {
     this._userInputStatus = document.getElementById(EXAM_CORRECT_USER_INPUT_STATUS_ID);
     this._userInputCandidates = document.getElementById(EXAM_CORRECT_USER_INPUT_CANDIDATES_ID);
     this._partInputs = [...this._element.querySelectorAll(`input[${EXAM_CORRECT_PART_INPUT_ATTR}]`)];
-    this._resultSelect = document.getElementById('uw-exam-correct__result').querySelector('select');
-    this._resultGradeSelect = document.getElementById('uw-exam-correct__result__grade').querySelector('select');
+    const resultCell = document.getElementById('uw-exam-correct__result');
+    this._resultSelect = resultCell && resultCell.querySelector('select');
+    const resultGradeCell = document.getElementById('uw-exam-correct__result__grade');
+    this._resultGradeSelect = resultGradeCell && resultGradeCell.querySelector('select');
     this._partDeleteBoxes = [...this._element.querySelectorAll('input.uw-exam-correct--delete-exam-part')];
 
     if (this._sendBtn)
@@ -114,15 +116,17 @@ export class ExamCorrect {
         .map((header) => [header.getAttribute('uw-exam-correct-header'), header.cellIndex])
     );
 
-    this._resultSelect.addEventListener('change', () => {
+    if (this._resultSelect && this._resultGradeSelect) {
+      this._resultSelect.addEventListener('change', () => {
+        if (this._resultSelect.value !== 'attended')
+          this._resultGradeSelect.classList.add('grade-hidden');
+        else
+          this._resultGradeSelect.classList.remove('grade-hidden');
+      });
+
       if (this._resultSelect.value !== 'attended')
         this._resultGradeSelect.classList.add('grade-hidden');
-      else
-        this._resultGradeSelect.classList.remove('grade-hidden');
-    });
-
-    if (this._resultSelect.value !== 'attended')
-      this._resultGradeSelect.classList.add('grade-hidden');
+    }
 
     this._lastColumnIndex = this._element.querySelector('thead > tr').querySelectorAll('th').length - 1;
 
@@ -235,7 +239,7 @@ export class ExamCorrect {
     }
 
     let result;
-    if (this._resultSelect) {
+    if (this._resultSelect && this._resultGradeSelect) {
       switch (this._resultSelect.value) {
         case 'none':
           result = undefined;
@@ -421,7 +425,7 @@ export class ExamCorrect {
             if (v === null) {
               resultCell.innerHTML = '<i class="fas fa-fw fa-trash"></i>';
               resultCell.classList.remove('exam-correct--result-unconfirmed');
-            } else if (v && v.result) {
+            } else if (v && v.result !== undefined && v.result !== null) {
               resultCell.innerHTML = v.result;
               resultCell.classList.remove('exam-correct--result-unconfirmed');
             }