diff --git a/backend/src/services/class.ts b/backend/src/services/class.ts
index 4f3cbc9d..52d841f4 100644
--- a/backend/src/services/class.ts
+++ b/backend/src/services/class.ts
@@ -25,13 +25,13 @@ export async function createClass(classData: ClassDTO): Promise<Class | null> {
     const teacherRepository = getTeacherRepository();
     const teacherUsernames = classData.teachers || [];
     const teachers = (await Promise.all(teacherUsernames.map(async (id) => teacherRepository.findByUsername(id)))).filter(
-        (teacher) => teacher != null
+        (teacher) => teacher !== null
     );
 
     const studentRepository = getStudentRepository();
     const studentUsernames = classData.students || [];
     const students = (await Promise.all(studentUsernames.map(async (id) => studentRepository.findByUsername(id)))).filter(
-        (student) => student != null
+        (student) => student !== null
     );
 
     //Const cls = mapToClass(classData, teachers, students);
diff --git a/backend/src/services/groups.ts b/backend/src/services/groups.ts
index 6abcd3fc..30be8b86 100644
--- a/backend/src/services/groups.ts
+++ b/backend/src/services/groups.ts
@@ -44,7 +44,7 @@ export async function createGroup(groupData: GroupDTO, classid: string, assignme
 
     const memberUsernames = (groupData.members as string[]) || []; // TODO check if groupdata.members is a list
     const members = (await Promise.all([...memberUsernames].map(async (id) => studentRepository.findByUsername(id)))).filter(
-        (student) => student != null
+        (student) => student !== null
     );
 
     getLogger().debug(members);
diff --git a/backend/tests/data/questions/answers.test.ts b/backend/tests/data/questions/answers.test.ts
index bcc62cf6..e53f1b5f 100644
--- a/backend/tests/data/questions/answers.test.ts
+++ b/backend/tests/data/questions/answers.test.ts
@@ -23,7 +23,7 @@ describe('AnswerRepository', () => {
         const id = new LearningObjectIdentifier('id05', Language.English, 1);
         const questions = await questionRepository.findAllQuestionsAboutLearningObject(id);
 
-        const question = questions.filter((it) => it.sequenceNumber == 2)[0];
+        const question = questions.filter((it) => it.sequenceNumber === 2)[0];
 
         const answers = await answerRepository.findAllAnswersToQuestion(question);