Prereq oaktree check if prereq course exists (#111)

* sidebar component add

* tailwind workin, beggining page building

* structure

* fixed app

* Main design layout

* initial sidebar

* courseView init

* the course page initial tests

* Make it run on my comuter

* Tree without database integration

* fixes

* npm update

* add to page

* Biiiiig Refactoring

* Broken version of prereq tree

* Fixed not rendering anything. Still broken

* Working v1

* handling #prereqs

* Test

* removed commented out code

* More info expands now

* More info expands now

* More info expands now

* Start coding on line 135 in PrereqTreePresenter Mr. PO

* Prereqs colored and expands more info

* added css styling

* Fixed copy bug

* Crash fix in PrerequisitePresenter.jsx

* merge fix

* Prereq tree compression, error handling, debuging, database update

* Added null support (hopefully)

* Bug fixes

* Desplays periods

* Bug finally fixed (hopefully)

* Check if course exists before doing pop up

---------

Co-authored-by: kexana <deotsts@gmail.com>
Co-authored-by: Sami Al Saati <sami.alsaati@hotmail.com>
Co-authored-by: Kacper Lisik <lisik@kth.se>
Co-authored-by: Elias Tosteberg <elias.tosteberg@gmail.com>
Co-authored-by: Sailet03 <52610280+Sailet03@users.noreply.github.com>

Author: 5 people

my-app/src/presenters/PrerequisitePresenter.jsx

@@ -132,7 +132,7 @@ export const PrerequisitePresenter = observer((props) => {
                 let inner_code = arr[1] + arr[2];
                 let course_name_inner = model.getCourse(inner_code)?.name;
                 if (!course_name_inner) {
-                    course_name_inner = "Course discontinued"
+                    course_name_inner = "Course discontinued";
                 }
                 course_name += "<li>" + inner_code + ": " + course_name_inner + "</li>"
             }
@@ -141,7 +141,11 @@ export const PrerequisitePresenter = observer((props) => {
         else if (node.data.label === "More Info...") {
             course_name = input_text_obj[node["id"]];
         } else {
-            course_name = model.getCourse(course_id).name;
+            if (model.getCourse(course_id)) {
+                course_name = model.getCourse(course_id).name;
+            } else {
+                course_name = "Course discontinued";
+            }
         }
 
         hover_popup.innerHTML = course_name;