Prevent removal of already removed menu sections from throwing errors

src/app/shared/menu/menu.reducer.spec.ts

@@ -388,6 +388,13 @@ describe('menusReducer', () => {
     expect(newState[menuID].sectionToSubsectionIndex[parentID]).not.toContain(childID);
   });
 
+  it('should not throw an error when trying to remove an already removed section using the REMOVE_SECTION action', () => {
+    const state = dummyState;
+    const action = new RemoveMenuSectionAction(menuID, 'non-existing-id');
+    const newState = menusReducer(state, action);
+    expect(newState).toEqual(dummyState);
+  });
+
   it('should set active to true for the correct menu section in response to the ACTIVATE_SECTION action', () => {
     dummyState[menuID].sections[topSectionID].active = false;
     const state = dummyState;

src/app/shared/menu/menu.reducer.ts

@@ -1,4 +1,7 @@
-import { hasValue } from '@dspace/shared/utils/empty.util';
+import {
+  hasNoValue,
+  hasValue,
+} from '@dspace/shared/utils/empty.util';
 
 import { initialMenusState } from './initial-menus-state';
 import {
@@ -149,11 +152,14 @@ function removeSection(state: MenusState, action: RemoveMenuSectionAction) {
 /**
  * Remove a section from the index of a certain menu
  * @param {MenusState} state The initial state
- * @param {MenuSection} action The MenuSection of which the ID should be removed from the index
- * @param {MenuID} action The Menu ID to which the section belonged
+ * @param {MenuSection} section The MenuSection of which the ID should be removed from the index
+ * @param {MenuID} menuID The Menu ID to which the section belonged
  * @returns {MenusState} The new reduced state
  */
 function removeFromIndex(state: MenusState, section: MenuSection, menuID: MenuID) {
+  if (hasNoValue(section)) {
+    return state;
+  }
   const sectionID = section.id;
   const parentID = section.parentID;
   if (hasValue(parentID)) {