diff --git a/backend/tests/services/learning-objects/database-learning-object-provider.test.ts b/backend/tests/services/learning-objects/database-learning-object-provider.test.ts
index b9e2a737..5170ea0f 100644
--- a/backend/tests/services/learning-objects/database-learning-object-provider.test.ts
+++ b/backend/tests/services/learning-objects/database-learning-object-provider.test.ts
@@ -38,7 +38,7 @@ describe('DatabaseLearningObjectProvider', () => {
         it('should return the learning object when it is queried by its id', async () => {
             const result: FilteredLearningObject | null = await databaseLearningObjectProvider.getLearningObjectById(exampleLearningObject);
             expect(result).toBeTruthy();
-            expectToBeCorrectFilteredLearningObject(result!, exampleLearningObject);
+            expectToBeCorrectFilteredLearningObject(result, exampleLearningObject);
         });
 
         it('should return the learning object when it is queried by only hruid and language (but not version)', async () => {
@@ -47,7 +47,7 @@ describe('DatabaseLearningObjectProvider', () => {
                 language: exampleLearningObject.language,
             });
             expect(result).toBeTruthy();
-            expectToBeCorrectFilteredLearningObject(result!, exampleLearningObject);
+            expectToBeCorrectFilteredLearningObject(result, exampleLearningObject);
         });
 
         it('should return null when queried with an id that does not exist', async () => {
diff --git a/frontend/src/queries/submissions.ts b/frontend/src/queries/submissions.ts
index 92e071ec..d1c1a6a2 100644
--- a/frontend/src/queries/submissions.ts
+++ b/frontend/src/queries/submissions.ts
@@ -63,7 +63,7 @@ export async function invalidateAllSubmissionKeys(
 }
 
 function checkEnabled(properties: MaybeRefOrGetter<unknown>[]): boolean {
-    return properties.every(prop => !!toValue(prop));
+    return properties.every(prop => Boolean(toValue(prop)));
 }
 
 export function useSubmissionsQuery(
@@ -87,7 +87,7 @@ export function useSubmissionsQuery(
             const fullVal = toValue(full);
 
             const response = await new SubmissionController(hruidVal!).getAll(
-                languageVal!, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal, fullVal
+                languageVal, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal, fullVal
             );
             return response ? response.submissions as SubmissionDTO[] : undefined;
         },
@@ -114,12 +114,12 @@ export function useSubmissionQuery(
 
     return useQuery({
         queryKey: computed(() => submissionQueryKey(
-            hruidVal!, languageVal!, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal!, submissionNumberVal!
+            hruidVal!, languageVal, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal!, submissionNumberVal!
         )),
         queryFn: async () => new SubmissionController(hruidVal!).getByNumber(
-            languageVal!, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal!, submissionNumberVal!
+            languageVal, versionVal!, classIdVal!, assignmentNumberVal!, groupNumberVal!, submissionNumberVal!
         ),
-        enabled: () => !!hruidVal && !!languageVal && !!versionVal && !!classIdVal && !!assignmentNumberVal && !!submissionNumber,
+        enabled: () => Boolean(hruidVal) && Boolean(languageVal) && Boolean(versionVal) && Boolean(classIdVal) && Boolean(assignmentNumberVal) && Boolean(submissionNumber),
     });
 }
 
diff --git a/frontend/src/utils/deep-equals.ts b/frontend/src/utils/deep-equals.ts
index 84afee2e..94099dc1 100644
--- a/frontend/src/utils/deep-equals.ts
+++ b/frontend/src/utils/deep-equals.ts
@@ -1,20 +1,20 @@
 export function deepEquals<T>(a: T, b: T): boolean {
-    if (a === b) return true;
+    if (a === b) {return true;}
 
     if (typeof a !== 'object' || typeof b !== 'object' || a == null || b == null)
-        return false;
+        {return false;}
 
-    if (Array.isArray(a) !== Array.isArray(b)) return false;
+    if (Array.isArray(a) !== Array.isArray(b)) {return false;}
 
     if (Array.isArray(a) && Array.isArray(b)) {
-        if (a.length !== b.length) return false;
+        if (a.length !== b.length) {return false;}
         return a.every((val, i) => deepEquals(val, b[i]));
     }
 
     const keysA = Object.keys(a) as (keyof T)[];
     const keysB = Object.keys(b) as (keyof T)[];
 
-    if (keysA.length !== keysB.length) return false;
+    if (keysA.length !== keysB.length) {return false;}
 
     return keysA.every(key => deepEquals(a[key], b[key]));
 }
diff --git a/frontend/src/views/learning-paths/gift-adapters/essay-question-adapter.ts b/frontend/src/views/learning-paths/gift-adapters/essay-question-adapter.ts
index eb49027c..554a4aab 100644
--- a/frontend/src/views/learning-paths/gift-adapters/essay-question-adapter.ts
+++ b/frontend/src/views/learning-paths/gift-adapters/essay-question-adapter.ts
@@ -3,7 +3,7 @@ export const essayQuestionAdapter: GiftAdapter = {
 
     installListener(questionElement: Element, answerUpdateCallback: (newAnswer: string | number | object) => void): void {
         const textArea = questionElement.querySelector('textarea')!;
-        textArea.addEventListener('input', () => answerUpdateCallback(textArea.value));
+        textArea.addEventListener('input', () => { answerUpdateCallback(textArea.value); });
     },
 
     setAnswer(questionElement: Element, answer: string | number | object): void {