fix(timetable): fix incorrect rendering of lecture slots (#3965)

Author: kaze-droid

website/src/utils/modules.test.ts

@@ -17,6 +17,7 @@ import {
   renderExamDuration,
   getExamDuration,
   canTa,
+  areLessonsDuplicate,
 } from 'utils/modules';
 import { noBreak } from 'utils/react';
 
@@ -93,6 +94,24 @@ test('areLessonsSameClass should identify lessons with different lessonType as d
   expect(areLessonsSameClass(mockLesson, otherLesson)).toBe(false);
 });
 
+test(
+  'areLessonsDuplicate should identify lessons from the same ClassNo but ' +
+    'with different timings as non duplicates',
+  () => {
+    const otherLesson: Lesson = lessonWithDifferentProperty(mockLesson, 'startTime', '0000');
+    expect(areLessonsDuplicate(mockLesson, otherLesson)).toBe(false);
+  },
+);
+
+test(
+  'areLessonsDuplicate should identify lessons from the same ClassNo but ' +
+    'with different day as non duplicates',
+  () => {
+    const otherLesson: Lesson = lessonWithDifferentProperty(mockLesson, 'day', 'Monday');
+    expect(areLessonsDuplicate(mockLesson, otherLesson)).toBe(false);
+  },
+);
+
 test('formatExamDate should format an exam date string correctly', () => {
   expect(formatExamDate('2016-11-23T01:00:00.000Z')).toBe('23-Nov-2016 9:00\u00a0AM');
   expect(formatExamDate('2016-01-23T01:00:00.000Z')).toBe('23-Jan-2016 9:00\u00a0AM');

website/src/utils/modules.ts

@@ -44,6 +44,17 @@ export function areLessonsSameClass(lesson1: Lesson, lesson2: Lesson): boolean {
   );
 }
 
+// Are the two lessons exact duplicates of one another
+export function areLessonsDuplicate(lesson1: Lesson, lesson2: Lesson): boolean {
+  return (
+    lesson1.moduleCode === lesson2.moduleCode &&
+    lesson1.classNo === lesson2.classNo &&
+    lesson1.lessonType === lesson2.lessonType &&
+    lesson1.day === lesson2.day &&
+    lesson1.startTime === lesson2.startTime
+  );
+}
+
 /**
  * Convert exam in ISO format to 12-hour date/time format.
  */

website/src/views/timetable/TimetableContent.tsx

@@ -26,6 +26,7 @@ import {
   resetTimetable,
 } from 'actions/timetables';
 import {
+  areLessonsDuplicate,
   areLessonsSameClass,
   canTa,
   formatExamDate,
@@ -378,7 +379,7 @@ class TimetableContent extends React.Component<Props, State> {
 
         // Prevent multiple versions of the same lesson
         if (
-          timetableLessons.some((curLesson) => areLessonsSameClass(modifiableLesson, curLesson))
+          timetableLessons.some((curLesson) => areLessonsDuplicate(modifiableLesson, curLesson))
         ) {
           return;
         }