szenario

apps/backend/src/renovation/furniture-pricing.ts

@@ -36,3 +36,9 @@ export function sumMoney(values: readonly (string | number)[]): string {
   const total = values.reduce<number>((sum, value) => sum + cents(value), 0);
   return `${Math.floor(total / 100)}.${String(total % 100).padStart(2, '0')}`;
 }
+
+export function formatOptionalMoney(
+  value: number | null | undefined,
+): string | null {
+  return value == null ? null : value.toFixed(2);
+}

apps/backend/src/renovation/furniture.service.ts

@@ -34,7 +34,11 @@ import {
   FurnitureScenarioStatus,
   FurnitureScenarioType,
 } from './entities/furniture.entities';
-import { calculateFurnitureTotal, sumMoney } from './furniture-pricing';
+import {
+  calculateFurnitureTotal,
+  formatOptionalMoney,
+  sumMoney,
+} from './furniture-pricing';
 import { FurnitureRepository } from './furniture.repository';
 import { RenovationRepository } from './renovation.repository';
 
@@ -1317,8 +1321,8 @@ export class FurnitureService {
         'Dieser Datensatz wurde zwischenzeitlich geändert. Laden Sie die aktuellen Daten neu.',
       );
   }
-  private decimal(value?: number) {
-    return value === undefined ? null : value.toFixed(2);
+  private decimal(value?: number | null) {
+    return formatOptionalMoney(value);
   }
   private validation(message: string): never {
     throw new ApiError(ErrorCode.ValidationFailed, message, 400);

apps/backend/src/renovation/tests/furniture-pricing.spec.ts

@@ -1,5 +1,9 @@
 import { describe, expect, it } from 'vitest';
-import { calculateFurnitureTotal, sumMoney } from '../furniture-pricing';
+import {
+  calculateFurnitureTotal,
+  formatOptionalMoney,
+  sumMoney,
+} from '../furniture-pricing';
 
 describe('furniture price calculation', () => {
   it('includes quantity, shipping and additional costs and subtracts discounts cent-exactly', () => {
@@ -40,4 +44,10 @@ describe('furniture price calculation', () => {
   it('sums decimal money without binary floating point drift', () => {
     expect(sumMoney(['0.10', '0.20', '1299.99'])).toBe('1300.29');
   });
+
+  it('formats optional scenario price overrides without crashing for missing values', () => {
+    expect(formatOptionalMoney(undefined)).toBeNull();
+    expect(formatOptionalMoney(null)).toBeNull();
+    expect(formatOptionalMoney(12.5)).toBe('12.50');
+  });
 });