diff --git a/app/components/SourcesChart.vue b/app/components/SourcesChart.vue
index 9c73b47da..e849b2674 100644
--- a/app/components/SourcesChart.vue
+++ b/app/components/SourcesChart.vue
@@ -2,12 +2,12 @@
 import type { SourceRaw, Source } from '~~/shared/classes.ts';
 
 const props = defineProps<{
-    sources: (SourceRaw | Source)[] | null;
+    sources: (SourceRaw | Source)[] | undefined;
     label: string;
 }>();
 
 const publishDates = computed(() => {
-    if (props.sources === null) {
+    if (props.sources === undefined) {
         return null;
     }
     const dates: Record<number, number> = {};
diff --git a/app/components/Stats.vue b/app/components/Stats.vue
index 8629d196c..d832bdffe 100644
--- a/app/components/Stats.vue
+++ b/app/components/Stats.vue
@@ -8,7 +8,7 @@ const heartbeatHost = runtimeConfig.public.heartbeatLink;
 const overall = ref(true);
 
 const activeStats = computed(() => {
-    if (stats.value === null) {
+    if (stats.value === undefined) {
         return undefined;
     }
 
diff --git a/app/components/VersionCommitLink.vue b/app/components/VersionCommitLink.vue
index db316a6b9..1516b693f 100644
--- a/app/components/VersionCommitLink.vue
+++ b/app/components/VersionCommitLink.vue
@@ -1,6 +1,6 @@
 <script setup lang="ts">
 defineProps<{
-    hash: string | null;
+    hash: string | undefined;
 }>();
 
 const base = 'https://gitlab.com/PronounsPage/PronounsPage/-/commit';
diff --git a/app/components/nouns/NounsDictionary.vue b/app/components/nouns/NounsDictionary.vue
index 6a0dccd9b..cf1f7ce54 100644
--- a/app/components/nouns/NounsDictionary.vue
+++ b/app/components/nouns/NounsDictionary.vue
@@ -55,7 +55,7 @@ const nounsAsyncData = useAsyncData(
 );
 
 const loadNouns = async (): Promise<void> => {
-    if (nounsAsyncData.data.value === null) {
+    if (nounsAsyncData.data.value === undefined) {
         await nounsAsyncData.execute();
     }
 };
diff --git a/app/components/pronouns/PronounsDetailPage.vue b/app/components/pronouns/PronounsDetailPage.vue
index d15d35439..ca6c0cea6 100644
--- a/app/components/pronouns/PronounsDetailPage.vue
+++ b/app/components/pronouns/PronounsDetailPage.vue
@@ -38,7 +38,7 @@ const pronounGroup = pronounLibrary.find(props.pronoun);
 const comprehensive = useComprehensive();
 
 const sourceLibrary = computed(() => {
-    if (sources.value === null) {
+    if (sources.value === undefined) {
         return null;
     }
     return new SourceLibrary(config, sources.value);
diff --git a/app/pages/admin/timesheets/index.vue b/app/pages/admin/timesheets/index.vue
index 91986cf81..dedd13a43 100644
--- a/app/pages/admin/timesheets/index.vue
+++ b/app/pages/admin/timesheets/index.vue
@@ -39,7 +39,7 @@ watch(year, () => {
     cells.value.get('1-0')?.focus();
 });
 
-const buildTimesheet = (persistent: TimesheetData | null): Timesheet => {
+const buildTimesheet = (persistent: TimesheetData | undefined): Timesheet => {
     const timesheet: Timesheet = {};
     for (let y = min.year; y <= max.year; y++) {
         timesheet[y] = {};
diff --git a/app/pages/sources.vue b/app/pages/sources.vue
index 9596ae743..83c31dd80 100644
--- a/app/pages/sources.vue
+++ b/app/pages/sources.vue
@@ -23,7 +23,7 @@ const filter = useFilterWithCategory();
 
 const { data: rawSources } = await useFetch('/api/sources', { lazy: true });
 const sourceLibrary = computed(() => {
-    if (rawSources.value === null) {
+    if (rawSources.value === undefined) {
         return undefined;
     }
     return new SourceLibrary(config, rawSources.value);