diff --git a/frontend/src/components/BrowseThemes.vue b/frontend/src/components/BrowseThemes.vue
index eeea2c81..97ff8352 100644
--- a/frontend/src/components/BrowseThemes.vue
+++ b/frontend/src/components/BrowseThemes.vue
@@ -1,47 +1,56 @@
 <script setup lang="ts">
-import ThemeCard from "@/components/ThemeCard.vue";
-import { ref, watchEffect, computed } from "vue";
-import { useI18n } from "vue-i18n";
-import { AGE_TO_THEMES, THEMESITEMS } from "@/utils/constants.ts";
-import { useThemeQuery } from "@/queries/themes.ts";
+    import ThemeCard from "@/components/ThemeCard.vue";
+    import { ref, watchEffect, computed } from "vue";
+    import { useI18n } from "vue-i18n";
+    import { AGE_TO_THEMES, THEMESITEMS } from "@/utils/constants.ts";
+    import { useThemeQuery } from "@/queries/themes.ts";
 
-const props = defineProps({
-    selectedTheme: { type: String, required: true },
-    selectedAge: { type: String, required: true }
-});
+    const props = defineProps({
+        selectedTheme: { type: String, required: true },
+        selectedAge: { type: String, required: true },
+    });
 
-const { locale } = useI18n();
-const language = computed(() => locale.value);
+    const { locale } = useI18n();
+    const language = computed(() => locale.value);
 
-const { data: allThemes, isLoading, error } = useThemeQuery(language);
+    const { data: allThemes, isLoading, error } = useThemeQuery(language);
 
-const allCards = ref([]);
-const cards = ref([]);
+    const allCards = ref([]);
+    const cards = ref([]);
 
-watchEffect(() => {
-    const themes = allThemes.value ?? [];
-    allCards.value = themes;
+    watchEffect(() => {
+        const themes = allThemes.value ?? [];
+        allCards.value = themes;
 
-    if (props.selectedTheme) {
-        cards.value = themes.filter((theme) =>
-            THEMESITEMS[props.selectedTheme]?.includes(theme.key) &&
-            AGE_TO_THEMES[props.selectedAge]?.includes(theme.key)
-        );
-    } else {
-        cards.value = themes;
-    }
-});
+        if (props.selectedTheme) {
+            cards.value = themes.filter(
+                (theme) =>
+                    THEMESITEMS[props.selectedTheme]?.includes(theme.key) &&
+                    AGE_TO_THEMES[props.selectedAge]?.includes(theme.key),
+            );
+        } else {
+            cards.value = themes;
+        }
+    });
 </script>
 
-
 <template>
     <v-container>
-        <div v-if="isLoading" class="text-center py-10">
-            <v-progress-circular indeterminate color="primary" />
+        <div
+            v-if="isLoading"
+            class="text-center py-10"
+        >
+            <v-progress-circular
+                indeterminate
+                color="primary"
+            />
             <p>Loading...</p>
         </div>
 
-        <div v-else-if="error" class="text-center py-10 text-error">
+        <div
+            v-else-if="error"
+            class="text-center py-10 text-error"
+        >
             <v-icon large>mdi-alert-circle</v-icon>
             <p>Error loading: {{ error.message }}</p>
         </div>
diff --git a/frontend/src/components/MenuBar.vue b/frontend/src/components/MenuBar.vue
index b098ba38..e1d27905 100644
--- a/frontend/src/components/MenuBar.vue
+++ b/frontend/src/components/MenuBar.vue
@@ -22,7 +22,7 @@
         { name: "English", code: "en" },
         { name: "Nederlands", code: "nl" },
         { name: "Français", code: "fr" },
-        { name: "Deutsch", code: "de" }
+        { name: "Deutsch", code: "de" },
     ]);
 
     // Logic to change the language of the website to the selected language
diff --git a/frontend/src/components/ThemeCard.vue b/frontend/src/components/ThemeCard.vue
index ac9b3904..7064b63c 100644
--- a/frontend/src/components/ThemeCard.vue
+++ b/frontend/src/components/ThemeCard.vue
@@ -1,14 +1,14 @@
 <script setup lang="ts">
-import { useI18n } from "vue-i18n";
+    import { useI18n } from "vue-i18n";
 
-const { t } = useI18n();
+    const { t } = useI18n();
 
-defineProps<{
-    path: string;
-    title: string;
-    description: string;
-    image: string;
-}>();
+    defineProps<{
+        path: string;
+        title: string;
+        description: string;
+        image: string;
+    }>();
 </script>
 
 <template>
@@ -31,7 +31,10 @@ defineProps<{
         </v-card-title>
         <v-card-text class="description flex-grow-1">{{ description }}</v-card-text>
         <v-card-actions>
-            <v-btn :to="`theme/${path}`" variant="text">
+            <v-btn
+                :to="`theme/${path}`"
+                variant="text"
+            >
                 {{ t("read-more") }}
             </v-btn>
         </v-card-actions>
@@ -39,36 +42,36 @@ defineProps<{
 </template>
 
 <style scoped>
-.theme-card {
-    display: flex;
-    flex-direction: column;
-    height: 100%;
-    padding: 1rem;
-    cursor: pointer;
-}
+    .theme-card {
+        display: flex;
+        flex-direction: column;
+        height: 100%;
+        padding: 1rem;
+        cursor: pointer;
+    }
 
-.theme-card:hover {
-    background-color: rgba(0, 0, 0, 0.03);
-}
+    .theme-card:hover {
+        background-color: rgba(0, 0, 0, 0.03);
+    }
 
-.title-container {
-    display: flex;
-    align-items: center;
-    gap: 10px;
-    text-align: left;
-    justify-content: flex-start;
-}
+    .title-container {
+        display: flex;
+        align-items: center;
+        gap: 10px;
+        text-align: left;
+        justify-content: flex-start;
+    }
 
-.title-image {
-    flex-shrink: 0;
-    border-radius: 5px;
-    margin-left: 0;
-}
+    .title-image {
+        flex-shrink: 0;
+        border-radius: 5px;
+        margin-left: 0;
+    }
 
-.title {
-    flex-grow: 1;
-    white-space: normal;
-    overflow-wrap: break-word;
-    word-break: break-word;
-}
+    .title {
+        flex-grow: 1;
+        white-space: normal;
+        overflow-wrap: break-word;
+        word-break: break-word;
+    }
 </style>
diff --git a/frontend/src/controllers/base-controller.ts b/frontend/src/controllers/base-controller.ts
index adc0c8c0..5456c9e8 100644
--- a/frontend/src/controllers/base-controller.ts
+++ b/frontend/src/controllers/base-controller.ts
@@ -1,4 +1,4 @@
-import {apiConfig} from "@/config.ts";
+import { apiConfig } from "@/config.ts";
 
 export class BaseController {
     protected baseUrl: string;
@@ -7,7 +7,7 @@ export class BaseController {
         this.baseUrl = `${apiConfig.baseUrl}/${basePath}`;
     }
 
-    protected async get<T>(path: string, queryParams?: Record<string, any>): Promise<T> {
+    protected async get<T>(path: string, queryParams?: Record<string, string | number | boolean>): Promise<T> {
         let url = `${this.baseUrl}${path}`;
         if (queryParams) {
             const query = new URLSearchParams();
diff --git a/frontend/src/controllers/controllers.ts b/frontend/src/controllers/controllers.ts
index b3bbeb61..639a8f1c 100644
--- a/frontend/src/controllers/controllers.ts
+++ b/frontend/src/controllers/controllers.ts
@@ -1,11 +1,11 @@
-import {ThemeController} from "@/controllers/themes.ts";
+import { ThemeController } from "@/controllers/themes.ts";
 
-export function controllerGetter<T>(Factory: new () => T): () => T {
+export function controllerGetter<T>(factory: new () => T): () => T {
     let instance: T | undefined;
 
     return (): T => {
         if (!instance) {
-            instance = new Factory();
+            instance = new factory();
         }
         return instance;
     };
diff --git a/frontend/src/controllers/themes.ts b/frontend/src/controllers/themes.ts
index 447c9248..d6c8be98 100644
--- a/frontend/src/controllers/themes.ts
+++ b/frontend/src/controllers/themes.ts
@@ -1,16 +1,16 @@
-import {BaseController} from "@/controllers/base-controller.ts";
+import { BaseController } from "@/controllers/base-controller.ts";
 
 export class ThemeController extends BaseController {
     constructor() {
         super("theme");
     }
 
-    getAll(language: string | null = null) {
+    async getAll(language: string | null = null): Promise<unknown> {
         const query = language ? { language } : undefined;
-        return this.get<any[]>("/", query);
+        return this.get("/", query);
     }
 
-    getHruidsByKey(themeKey: string) {
+    async getHruidsByKey(themeKey: string): Promise<string[]> {
         return this.get<string[]>(`/${encodeURIComponent(themeKey)}`);
     }
 }
diff --git a/frontend/src/main.ts b/frontend/src/main.ts
index fc531957..5945a2ab 100644
--- a/frontend/src/main.ts
+++ b/frontend/src/main.ts
@@ -10,7 +10,7 @@ import i18n from "./i18n/i18n.ts";
 // Components
 import App from "./App.vue";
 import router from "./router";
-import { VueQueryPlugin, QueryClient } from '@tanstack/vue-query';
+import { VueQueryPlugin, QueryClient } from "@tanstack/vue-query";
 
 const app = createApp(App);
 
diff --git a/frontend/src/queries/themes.ts b/frontend/src/queries/themes.ts
index 9892c141..f7ecaf45 100644
--- a/frontend/src/queries/themes.ts
+++ b/frontend/src/queries/themes.ts
@@ -1,25 +1,24 @@
-import { useQuery } from '@tanstack/vue-query';
-import { getThemeController } from '@/controllers/controllers';
-import {type MaybeRefOrGetter, toValue} from "vue";
+import { useQuery, UseQueryReturnType } from "@tanstack/vue-query";
+import { getThemeController } from "@/controllers/controllers";
+import { type MaybeRefOrGetter, toValue } from "vue";
 
 const themeController = getThemeController();
 
-export const useThemeQuery = (language: MaybeRefOrGetter<string>) => {
+export function useThemeQuery(language: MaybeRefOrGetter<string>): UseQueryReturnType<never, Error> {
     return useQuery({
-        queryKey: ['themes', language],
-        queryFn: () => {
+        queryKey: ["themes", language],
+        queryFn: async () => {
             const lang = toValue(language);
             return themeController.getAll(lang);
         },
-        enabled: () => !!toValue(language),
+        enabled: () => Boolean(toValue(language)),
     });
-};
+}
 
-export const useThemeHruidsQuery = (themeKey: string | null) => {
+export function useThemeHruidsQuery(themeKey: string | null): UseQueryReturnType<never, Error> {
     return useQuery({
-        queryKey: ['theme-hruids', themeKey],
-        queryFn: () => themeController.getHruidsByKey(themeKey!),
-        enabled: !!themeKey,
+        queryKey: ["theme-hruids", themeKey],
+        queryFn: async () => themeController.getHruidsByKey(themeKey!),
+        enabled: Boolean(themeKey),
     });
-};
-
+}
diff --git a/frontend/src/utils/constants.ts b/frontend/src/utils/constants.ts
index e046d9c3..b56437d7 100644
--- a/frontend/src/utils/constants.ts
+++ b/frontend/src/utils/constants.ts
@@ -1,37 +1,64 @@
 export const THEMES_KEYS = [
-    "kiks", "art", "socialrobot", "agriculture", "wegostem",
-    "computational_thinking", "math_with_python", "python_programming",
-    "stem", "care", "chatbot", "physical_computing", "algorithms", "basics_ai"
+    "kiks",
+    "art",
+    "socialrobot",
+    "agriculture",
+    "wegostem",
+    "computational_thinking",
+    "math_with_python",
+    "python_programming",
+    "stem",
+    "care",
+    "chatbot",
+    "physical_computing",
+    "algorithms",
+    "basics_ai",
 ];
 
 export const THEMESITEMS: Record<string, string[]> = {
-    "all": THEMES_KEYS,
-    "culture": ["art", "wegostem", "chatbot"],
+    all: THEMES_KEYS,
+    culture: ["art", "wegostem", "chatbot"],
     "electricity-and-mechanics": ["socialrobot", "wegostem", "stem", "physical_computing"],
     "nature-and-climate": ["kiks", "agriculture"],
-    "agriculture": ["agriculture"],
-    "society": ["kiks", "socialrobot", "care", "chatbot"],
-    "math": ["kiks", "math_with_python", "python_programming", "stem", "care", "basics_ai"],
-    "technology": ["socialrobot", "wegostem", "computational_thinking", "stem", "physical_computing", "basics_ai"],
-    "algorithms": ["math_with_python", "python_programming", "stem", "algorithms", "basics_ai"],
+    agriculture: ["agriculture"],
+    society: ["kiks", "socialrobot", "care", "chatbot"],
+    math: ["kiks", "math_with_python", "python_programming", "stem", "care", "basics_ai"],
+    technology: ["socialrobot", "wegostem", "computational_thinking", "stem", "physical_computing", "basics_ai"],
+    algorithms: ["math_with_python", "python_programming", "stem", "algorithms", "basics_ai"],
 };
 
-export const AGEITEMS = [
-    "all", "primary-school", "lower-secondary", "upper-secondary", "high-school", "older"
-];
+export const AGEITEMS = ["all", "primary-school", "lower-secondary", "upper-secondary", "high-school", "older"];
 
 export const AGE_TO_THEMES: Record<string, string[]> = {
-    "all": THEMES_KEYS,
+    all: THEMES_KEYS,
     "primary-school": ["wegostem", "computational_thinking", "physical_computing"],
     "lower-secondary": ["socialrobot", "art", "wegostem", "computational_thinking", "physical_computing"],
-    "upper-secondary": ["kiks", "art", "socialrobot", "agriculture",
-        "computational_thinking", "math_with_python", "python_programming",
-        "stem", "care", "chatbot", "algorithms", "basics_ai"],
-    "high-school": [
-        "kiks", "art", "agriculture", "computational_thinking", "math_with_python", "python_programming",
-        "stem", "care", "chatbot", "algorithms", "basics_ai"
+    "upper-secondary": [
+        "kiks",
+        "art",
+        "socialrobot",
+        "agriculture",
+        "computational_thinking",
+        "math_with_python",
+        "python_programming",
+        "stem",
+        "care",
+        "chatbot",
+        "algorithms",
+        "basics_ai",
     ],
-    "older": [
-        "kiks", "computational_thinking", "algorithms", "basics_ai"
-    ]
+    "high-school": [
+        "kiks",
+        "art",
+        "agriculture",
+        "computational_thinking",
+        "math_with_python",
+        "python_programming",
+        "stem",
+        "care",
+        "chatbot",
+        "algorithms",
+        "basics_ai",
+    ],
+    older: ["kiks", "computational_thinking", "algorithms", "basics_ai"],
 };
diff --git a/frontend/src/views/SingleTheme.vue b/frontend/src/views/SingleTheme.vue
index 73336fa3..1a35a59f 100644
--- a/frontend/src/views/SingleTheme.vue
+++ b/frontend/src/views/SingleTheme.vue
@@ -1,11 +1,7 @@
-<script setup lang="ts">
-
-</script>
+<script setup lang="ts"></script>
 
 <template>
-<main></main>
+    <main></main>
 </template>
 
-<style scoped>
-
-</style>
+<style scoped></style>
diff --git a/frontend/src/views/homepage/UserHomePage.vue b/frontend/src/views/homepage/UserHomePage.vue
index b6cdea17..c4f933a5 100644
--- a/frontend/src/views/homepage/UserHomePage.vue
+++ b/frontend/src/views/homepage/UserHomePage.vue
@@ -1,13 +1,13 @@
 <script setup lang="ts">
-import {ref, watch} from "vue";
-    import {useI18n} from "vue-i18n";
-    import {THEMESITEMS, AGE_TO_THEMES} from "@/utils/constants.ts";
+    import { ref, watch } from "vue";
+    import { useI18n } from "vue-i18n";
+    import { THEMESITEMS, AGE_TO_THEMES } from "@/utils/constants.ts";
     import BrowseThemes from "@/components/BrowseThemes.vue";
 
-    const {t, locale} = useI18n();
+    const { t, locale } = useI18n();
 
-    const selectedThemeKey = ref<string>('all');
-    const selectedAgeKey = ref<string>('all');
+    const selectedThemeKey = ref<string>("all");
+    const selectedAgeKey = ref<string>("all");
 
     const allThemes = ref(Object.keys(THEMESITEMS));
     const availableThemes = ref([...allThemes.value]);
@@ -17,18 +17,17 @@ import {ref, watch} from "vue";
 
     // Reset selection when language changes
     watch(locale, () => {
-        selectedThemeKey.value = 'all';
-        selectedAgeKey.value = 'all';
+        selectedThemeKey.value = "all";
+        selectedAgeKey.value = "all";
     });
 
-
     watch(selectedThemeKey, () => {
         if (selectedThemeKey.value === "all") {
             availableAges.value = [...allAges.value]; // Reset to all ages
         } else {
             const themes = THEMESITEMS[selectedThemeKey.value];
-            availableAges.value = allAges.value.filter(age =>
-                AGE_TO_THEMES[age]?.some(theme => themes.includes(theme))
+            availableAges.value = allAges.value.filter((age) =>
+                AGE_TO_THEMES[age]?.some((theme) => themes.includes(theme)),
             );
         }
     });
@@ -38,32 +37,31 @@ import {ref, watch} from "vue";
             availableThemes.value = [...allThemes.value]; // Reset to all themes
         } else {
             const themes = AGE_TO_THEMES[selectedAgeKey.value];
-            availableThemes.value = allThemes.value.filter(theme =>
-                THEMESITEMS[theme]?.some(theme => themes.includes(theme))
+            availableThemes.value = allThemes.value.filter((theme) =>
+                THEMESITEMS[theme]?.some((theme) => themes.includes(theme)),
             );
         }
     });
-
 </script>
 
 <template>
     <div class="main-container">
         <h1 class="title">{{ t("themes") }}</h1>
         <v-container class="dropdowns">
-            <v-select class="v-select"
-                      :label="t('choose-theme')"
-                      :items="availableThemes.map(theme => ({ title: t(`theme-options.${theme}`), value: theme }))"
-                      v-model="selectedThemeKey"
-                      item-title="title"
-                      item-value="value"
-                      variant="outlined"
+            <v-select
+                class="v-select"
+                :label="t('choose-theme')"
+                :items="availableThemes.map((theme) => ({ title: t(`theme-options.${theme}`), value: theme }))"
+                v-model="selectedThemeKey"
+                item-title="title"
+                item-value="value"
+                variant="outlined"
             />
 
-
             <v-select
                 class="v-select"
                 :label="t('choose-age')"
-                :items="availableAges.map(age => ({ key: age, label: t(`age-options.${age}`), value: age }))"
+                :items="availableAges.map((age) => ({ key: age, label: t(`age-options.${age}`), value: age }))"
                 v-model="selectedAgeKey"
                 item-title="label"
                 item-value="key"
@@ -71,55 +69,55 @@ import {ref, watch} from "vue";
             ></v-select>
         </v-container>
 
-        <BrowseThemes :selectedTheme="selectedThemeKey ?? ''" :selectedAge="selectedAgeKey ?? ''"/>
+        <BrowseThemes
+            :selectedTheme="selectedThemeKey ?? ''"
+            :selectedAge="selectedAgeKey ?? ''"
+        />
     </div>
 </template>
 
 <style scoped>
-.main-container {
-    min-height: 100vh;
-    min-width: 100vw;
-    display: flex;
-    flex-direction: column;
-    align-items: flex-start;
-    justify-content: flex-start;
-}
-
-.title {
-    max-width: 50rem;
-    margin-left: 1rem;
-    margin-top: 1rem;
-    text-align: center;
-    display: flex;
-    justify-content: center;
-}
-
-
-.dropdowns {
-    display: flex;
-    justify-content: space-between;
-    gap: 5rem;
-    width: 80%;
-}
-
-.v-select {
-    flex: 1;
-    min-width: 100px;
-}
-
-
-@media (max-width: 768px) {
     .main-container {
-        padding: 1rem;
-    }
-}
-
-@media (max-width: 700px) {
-    .dropdowns {
+        min-height: 100vh;
+        min-width: 100vw;
+        display: flex;
         flex-direction: column;
-        gap: 1rem;
+        align-items: flex-start;
+        justify-content: flex-start;
+    }
+
+    .title {
+        max-width: 50rem;
+        margin-left: 1rem;
+        margin-top: 1rem;
+        text-align: center;
+        display: flex;
+        justify-content: center;
+    }
+
+    .dropdowns {
+        display: flex;
+        justify-content: space-between;
+        gap: 5rem;
         width: 80%;
     }
-}
 
+    .v-select {
+        flex: 1;
+        min-width: 100px;
+    }
+
+    @media (max-width: 768px) {
+        .main-container {
+            padding: 1rem;
+        }
+    }
+
+    @media (max-width: 700px) {
+        .dropdowns {
+            flex-direction: column;
+            gap: 1rem;
+            width: 80%;
+        }
+    }
 </style>