fix: standardize frontend date formatting with shared utility (Closes #175)

src/components/FeeRuleEditor.vue

@@ -200,6 +200,7 @@ import { reactive, ref, computed, onMounted } from 'vue'
 import { NcButton, NcLoadingIcon } from '@nextcloud/vue'
 import { useFeesStore } from '../stores/fees.js'
 import Plus from 'vue-material-design-icons/Plus.vue'
+import { formatDate } from '../utils/dateFormat.js'
 
 const feesStore = useFeesStore()
 
@@ -312,18 +313,7 @@ function formatCurrency(value) {
 	}).format(value)
 }
 
-function formatDate(dateStr) {
-	if (!dateStr) return '--'
-	try {
-		return new Date(dateStr).toLocaleDateString('de-DE', {
-			year: 'numeric',
-			month: '2-digit',
-			day: '2-digit',
-		})
-	} catch {
-		return dateStr
-	}
-}
+// formatDate imported from utils/dateFormat.js
 </script>
 
 <style scoped>

src/components/FileExplorer.vue

@@ -74,7 +74,7 @@
 							{{ file.type === 'folder' ? '—' : formatSize(file.size) }}
 						</td>
 						<td class="file-explorer__td file-explorer__td--date">
-							{{ formatDate(file.mtime) }}
+							{{ formatTimestamp(file.mtime) }}
 						</td>
 					</tr>
 				</tbody>
@@ -93,6 +93,7 @@ import Folder from 'vue-material-design-icons/Folder.vue'
 import FolderPlus from 'vue-material-design-icons/FolderPlus.vue'
 import File from 'vue-material-design-icons/File.vue'
 import OpenInNew from 'vue-material-design-icons/OpenInNew.vue'
+import { formatTimestamp } from '../utils/dateFormat.js'
 
 const props = defineProps({
 	memberId: {
@@ -172,23 +173,7 @@ function formatSize(bytes) {
 	return size + ' ' + units[i]
 }
 
-/**
- * Format a Unix timestamp as a human-readable date.
- *
- * @param {number} timestamp - Unix timestamp in seconds
- * @returns {string} Formatted date
- */
-function formatDate(timestamp) {
-	if (!timestamp) return '—'
-	const date = new Date(timestamp * 1000)
-	return date.toLocaleDateString('de-DE', {
-		day: '2-digit',
-		month: '2-digit',
-		year: 'numeric',
-		hour: '2-digit',
-		minute: '2-digit',
-	})
-}
+// formatTimestamp imported from utils/dateFormat.js
 </script>
 
 <style scoped>

src/utils/dateFormat.js

@@ -0,0 +1,71 @@
+/**
+ * Shared date formatting utilities for consistent German date display.
+ *
+ * All views should use these functions instead of inline toLocaleDateString()
+ * calls to ensure consistent formatting across the application.
+ *
+ * Part of Issue #175.
+ */
+
+/**
+ * Format a date string (ISO 8601) as a German date (dd.mm.yyyy).
+ *
+ * @param {string|null|undefined} dateStr ISO date string (e.g. "2026-04-10")
+ * @returns {string} Formatted date or em-dash if empty
+ */
+export function formatDate(dateStr) {
+	if (!dateStr) return '\u2014'
+	try {
+		return new Date(dateStr).toLocaleDateString('de-DE', {
+			day: '2-digit',
+			month: '2-digit',
+			year: 'numeric',
+		})
+	} catch {
+		return dateStr
+	}
+}
+
+/**
+ * Format a date string (ISO 8601) as a German date+time (dd.mm.yyyy, hh:mm:ss).
+ *
+ * @param {string|null|undefined} dateStr ISO datetime string
+ * @returns {string} Formatted datetime or em-dash if empty
+ */
+export function formatDateTime(dateStr) {
+	if (!dateStr) return '\u2014'
+	try {
+		return new Date(dateStr).toLocaleString('de-DE', {
+			day: '2-digit',
+			month: '2-digit',
+			year: 'numeric',
+			hour: '2-digit',
+			minute: '2-digit',
+			second: '2-digit',
+		})
+	} catch {
+		return dateStr
+	}
+}
+
+/**
+ * Format a Unix timestamp (seconds) as a German date+time.
+ *
+ * @param {number|null|undefined} timestamp Unix timestamp in seconds
+ * @returns {string} Formatted datetime or em-dash if empty
+ */
+export function formatTimestamp(timestamp) {
+	if (!timestamp) return '\u2014'
+	try {
+		const date = new Date(timestamp * 1000)
+		return date.toLocaleDateString('de-DE', {
+			day: '2-digit',
+			month: '2-digit',
+			year: 'numeric',
+			hour: '2-digit',
+			minute: '2-digit',
+		})
+	} catch {
+		return String(timestamp)
+	}
+}

src/views/AuditLog.vue

@@ -91,7 +91,7 @@
 					:key="entry.id"
 					class="audit-log__row">
 					<td class="audit-log__td audit-log__td--time">
-						{{ formatDate(entry.zeitpunkt) }}
+						{{ formatDateTime(entry.zeitpunkt) }}
 					</td>
 					<td class="audit-log__td">
 						{{ entry.ncUserId }}
@@ -148,6 +148,7 @@ import { onMounted } from 'vue'
 import { useRouter } from 'vue-router'
 import { NcButton, NcTextField, NcEmptyContent, NcLoadingIcon } from '@nextcloud/vue'
 import { useAuditLogStore } from '../stores/auditlog.js'
+import { formatDateTime } from '../utils/dateFormat.js'
 
 const store = useAuditLogStore()
 const router = useRouter()
@@ -170,18 +171,7 @@ function reload() {
 	store.fetchEntries()
 }
 
-function formatDate(dateStr) {
-	if (!dateStr) return '—'
-	const d = new Date(dateStr)
-	return d.toLocaleString('de-DE', {
-		day: '2-digit',
-		month: '2-digit',
-		year: 'numeric',
-		hour: '2-digit',
-		minute: '2-digit',
-		second: '2-digit',
-	})
-}
+// formatDateTime imported from utils/dateFormat.js
 
 function formatAktion(aktion) {
 	const map = {

src/views/FeeOverview.vue

@@ -208,6 +208,7 @@ import { ref, computed, onMounted } from 'vue'
 import { NcButton, NcLoadingIcon, NcEmptyContent } from '@nextcloud/vue'
 import { useFeesStore } from '../stores/fees.js'
 import { useMembersStore } from '../stores/members.js'
+import { formatDate } from '../utils/dateFormat.js'
 
 const feesStore = useFeesStore()
 const membersStore = useMembersStore()
@@ -327,10 +328,7 @@ async function saveNotes(recordId) {
 
 // ── Formatting ──────────────────────────────────────────────────────
 
-function formatDate(dateStr) {
-	if (!dateStr) return '--'
-	return new Date(dateStr).toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 function formatCurrency(value) {
 	if (value === null || value === undefined || isNaN(value)) return '--'

src/views/InjuryList.vue

@@ -95,6 +95,7 @@ import { ref, onMounted } from 'vue'
 import { NcButton } from '@nextcloud/vue'
 import { useInjuryStore } from '../stores/injuries.js'
 import InjuryForm from '../components/InjuryForm.vue'
+import { formatDate } from '../utils/dateFormat.js'
 
 const injuryStore = useInjuryStore()
 
@@ -103,10 +104,7 @@ const editingInjury = ref(null)
 const filterDateFrom = ref('')
 const filterDateTo = ref('')
 
-function formatDate(dateStr) {
-	if (!dateStr) return '-'
-	return new Date(dateStr).toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 function truncate(text, maxLen) {
 	if (!text) return ''

src/views/LagerDetail.vue

@@ -101,6 +101,7 @@ import { ref, computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
 import { NcButton } from '@nextcloud/vue'
 import { useLagerStore } from '../stores/lager.js'
+import { formatDate } from '../utils/dateFormat.js'
 
 const route = useRoute()
 const lagerStore = useLagerStore()
@@ -110,10 +111,7 @@ const newRolle = ref('Teilnehmer')
 
 const camp = computed(() => lagerStore.currentCamp)
 
-function formatDate(dateStr) {
-	if (!dateStr) return '-'
-	return new Date(dateStr).toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 async function doAddTeilnehmer() {
 	if (!newMemberId.value) return

src/views/LagerList.vue

@@ -121,6 +121,7 @@ import { ref, onMounted } from 'vue'
 import { NcButton } from '@nextcloud/vue'
 import { useLagerStore } from '../stores/lager.js'
 import { useStufenStore } from '../stores/stufen.js'
+import { formatDate } from '../utils/dateFormat.js'
 
 const lagerStore = useLagerStore()
 const stufenStore = useStufenStore()
@@ -128,11 +129,7 @@ const stufenStore = useStufenStore()
 const showCreate = ref(false)
 const newCamp = ref({ name: '', startdatum: '', enddatum: '', ort: '', beschreibung: '' })
 
-function formatDate(dateStr) {
-	if (!dateStr) return '-'
-	const d = new Date(dateStr)
-	return d.toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 function onYearChange(val) {
 	lagerStore.filterYear = val ? parseInt(val) : null

src/views/MemberList.vue

@@ -147,6 +147,7 @@ import Plus from 'vue-material-design-icons/Plus.vue'
 import AlertCircle from 'vue-material-design-icons/AlertCircle.vue'
 import AccountGroup from 'vue-material-design-icons/AccountGroup.vue'
 import SortIcon from '../components/SortIcon.vue'
+import { formatDate } from '../utils/dateFormat.js'
 
 const store = useMembersStore()
 const stufenStore = useStufenStore()
@@ -235,10 +236,7 @@ function getStufeNameById(stufeId) {
 /**
  * Calculate age from birthday string.
  */
-function formatDate(dateStr) {
-	if (!dateStr) return '—'
-	return new Date(dateStr).toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 function calculateAge(geburtsdatum) {
 	if (!geburtsdatum) return '—'

src/views/QueryBuilder.vue

@@ -128,6 +128,7 @@ import QueryBuilderComponent from '../components/QueryBuilder.vue'
 import Delete from 'vue-material-design-icons/Delete.vue'
 import Play from 'vue-material-design-icons/Play.vue'
 import ContentSave from 'vue-material-design-icons/ContentSave.vue'
+import { formatDate } from '../utils/dateFormat.js'
 
 const router = useRouter()
 const store = useQueriesStore()
@@ -195,10 +196,7 @@ function resetQuery() {
 	store.clearResults()
 }
 
-function formatDate(dateStr) {
-	if (!dateStr) return '—'
-	return new Date(dateStr).toLocaleDateString('de-DE')
-}
+// formatDate imported from utils/dateFormat.js
 
 function openMember(id) {
 	router.push({ name: 'member-detail', params: { id } })