refactor(contacts): extract error helper, field labels, match type labels

- Create lib/utils/error-helpers.ts with getErrorMessage() utility
  (replaces inline `e instanceof Error` pattern in archive + data pages)
- Create lib/constants/contact-fields.ts with CONTACT_FIELD_LABELS,
  COMPARISON_FIELDS, and getMatchTypeLabel()
  (deduplicated from MergeModal + duplicates page)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/contacts/apps/web/src/lib/components/duplicates/MergeModal.svelte

@@ -2,6 +2,7 @@
 	import { _ } from 'svelte-i18n';
 	import type { Contact } from '$lib/api/contacts';
 	import { getDisplayName, getInitials } from '$lib/utils/contact-display';
+	import { CONTACT_FIELD_LABELS, getMatchTypeLabel } from '$lib/constants/contact-fields';
 
 	interface Props {
 		isOpen: boolean;
@@ -25,17 +26,6 @@
 		}
 	});
 
-	function getMatchTypeLabel(type: 'email' | 'phone' | 'name') {
-		switch (type) {
-			case 'email':
-				return 'E-Mail';
-			case 'phone':
-				return 'Telefon';
-			case 'name':
-				return 'Name';
-		}
-	}
-
 	function getFieldValue(contact: Contact, field: keyof Contact): string {
 		const value = contact[field];
 		if (value === null || value === undefined) return '-';
@@ -52,16 +42,20 @@
 	}
 
 	// Fields to display in comparison
-	const comparisonFields: { key: keyof Contact; label: string }[] = [
-		{ key: 'firstName', label: 'Vorname' },
-		{ key: 'lastName', label: 'Nachname' },
-		{ key: 'email', label: 'E-Mail' },
-		{ key: 'phone', label: 'Telefon' },
-		{ key: 'mobile', label: 'Mobil' },
-		{ key: 'company', label: 'Firma' },
-		{ key: 'jobTitle', label: 'Position' },
-		{ key: 'city', label: 'Stadt' },
+	const comparisonFieldKeys: (keyof Contact)[] = [
+		'firstName',
+		'lastName',
+		'email',
+		'phone',
+		'mobile',
+		'company',
+		'jobTitle',
+		'city',
 	];
+	const comparisonFields = comparisonFieldKeys.map((key) => ({
+		key,
+		label: CONTACT_FIELD_LABELS[key] || key,
+	}));
 </script>
 
 {#if isOpen}

apps/contacts/apps/web/src/lib/constants/contact-fields.ts

@@ -0,0 +1,27 @@
+export const CONTACT_FIELD_LABELS: Record<string, string> = {
+	firstName: 'Vorname',
+	lastName: 'Nachname',
+	email: 'E-Mail',
+	phone: 'Telefon',
+	mobile: 'Mobil',
+	company: 'Firma',
+	jobTitle: 'Position',
+	street: 'Straße',
+	city: 'Stadt',
+	postalCode: 'Postleitzahl',
+	country: 'Land',
+	website: 'Webseite',
+	notes: 'Notizen',
+	birthday: 'Geburtstag',
+};
+
+export function getMatchTypeLabel(type: 'email' | 'phone' | 'name'): string {
+	switch (type) {
+		case 'email':
+			return 'E-Mail';
+		case 'phone':
+			return 'Telefon';
+		case 'name':
+			return 'Name';
+	}
+}

apps/contacts/apps/web/src/lib/utils/error-helpers.ts

@@ -0,0 +1,6 @@
+export function getErrorMessage(
+	error: unknown,
+	fallback: string = 'Ein Fehler ist aufgetreten'
+): string {
+	return error instanceof Error ? error.message : fallback;
+}

apps/contacts/apps/web/src/routes/(app)/archive/+page.svelte

@@ -5,6 +5,7 @@
 	import type { Contact } from '$lib/api/contacts';
 	import { getDisplayName, getInitials } from '$lib/utils/contact-display';
 	import { ContactListSkeleton } from '$lib/components/skeletons';
+	import { getErrorMessage } from '$lib/utils/error-helpers';
 	import '$lib/i18n';
 	import {
 		CaretLeft,
@@ -42,7 +43,7 @@
 			const result = await contactsApi.list({ isArchived: true });
 			contacts = result.contacts || result;
 		} catch (e) {
-			error = e instanceof Error ? e.message : 'Fehler beim Laden des Archivs';
+			error = getErrorMessage(e, 'Fehler beim Laden des Archivs');
 		} finally {
 			loading = false;
 		}
@@ -58,7 +59,7 @@
 			await contactsApi.toggleArchive(contact.id);
 			contacts = contacts.filter((c) => c.id !== contact.id);
 		} catch (e) {
-			error = e instanceof Error ? e.message : 'Fehler beim Wiederherstellen';
+			error = getErrorMessage(e, 'Fehler beim Wiederherstellen');
 		}
 	}
 
@@ -70,7 +71,7 @@
 			await contactsApi.delete(contact.id);
 			contacts = contacts.filter((c) => c.id !== contact.id);
 		} catch (e) {
-			error = e instanceof Error ? e.message : 'Fehler beim Löschen';
+			error = getErrorMessage(e, 'Fehler beim Löschen');
 		}
 	}
 

apps/contacts/apps/web/src/routes/(app)/data/+page.svelte

@@ -18,6 +18,7 @@
 		AddressBook,
 		Check,
 	} from '@manacore/shared-icons';
+	import { getErrorMessage } from '$lib/utils/error-helpers';
 	import '$lib/i18n';
 
 	type Tab = 'import' | 'export';
@@ -105,7 +106,7 @@
 			preview = await importApi.preview(file);
 			importStep = 'preview';
 		} catch (e) {
-			importError = e instanceof Error ? e.message : 'Fehler beim Verarbeiten der Datei';
+			importError = getErrorMessage(e, 'Fehler beim Verarbeiten der Datei');
 		} finally {
 			isLoading = false;
 		}
@@ -124,7 +125,7 @@
 			ContactsEvents.contactImported(fileExt as 'csv' | 'vcard', importResult?.imported);
 			// Live query auto-updates — no manual reload needed
 		} catch (e) {
-			importError = e instanceof Error ? e.message : 'Fehler beim Importieren';
+			importError = getErrorMessage(e, 'Fehler beim Importieren');
 		} finally {
 			isImporting = false;
 		}
@@ -146,7 +147,7 @@
 		try {
 			await importApi.downloadTemplate();
 		} catch (e) {
-			importError = e instanceof Error ? e.message : 'Fehler beim Herunterladen';
+			importError = getErrorMessage(e, 'Fehler beim Herunterladen');
 		}
 	}
 
@@ -164,7 +165,7 @@
 			});
 			exportSuccess = true;
 		} catch (e) {
-			exportError = e instanceof Error ? e.message : 'Export fehlgeschlagen';
+			exportError = getErrorMessage(e, 'Export fehlgeschlagen');
 		} finally {
 			isExporting = false;
 		}

apps/contacts/apps/web/src/routes/(app)/duplicates/+page.svelte

@@ -5,8 +5,10 @@
 	import MergeModal from '$lib/components/duplicates/MergeModal.svelte';
 	import { DuplicateListSkeleton } from '$lib/components/skeletons';
 	import { toastStore } from '@manacore/shared-ui';
+	import { getErrorMessage } from '$lib/utils/error-helpers';
 	import { ArrowsClockwise } from '@manacore/shared-icons';
 	import { getDisplayName, getInitials } from '$lib/utils/contact-display';
+	import { getMatchTypeLabel } from '$lib/constants/contact-fields';
 
 	let duplicates = $state<DuplicateGroup[]>([]);
 	let loading = $state(true);
@@ -21,24 +23,13 @@
 			const result = await duplicatesApi.findDuplicates();
 			duplicates = result.duplicates;
 		} catch (e) {
-			error = e instanceof Error ? e.message : 'Fehler beim Laden der Duplikate';
+			error = getErrorMessage(e, 'Fehler beim Laden der Duplikate');
 			console.error('Failed to load duplicates:', e);
 		} finally {
 			loading = false;
 		}
 	}
 
-	function getMatchTypeLabel(type: 'email' | 'phone' | 'name') {
-		switch (type) {
-			case 'email':
-				return 'E-Mail';
-			case 'phone':
-				return 'Telefon';
-			case 'name':
-				return 'Name';
-		}
-	}
-
 	function getMatchTypeIcon(type: 'email' | 'phone' | 'name') {
 		switch (type) {
 			case 'email':
@@ -70,7 +61,7 @@
 			}
 			handleCloseMergeModal();
 		} catch (e) {
-			toastStore.error(e instanceof Error ? e.message : 'Fehler beim Zusammenführen');
+			toastStore.error(getErrorMessage(e, 'Fehler beim Zusammenführen'));
 		}
 	}