fix(delivery-schedule): correct weekday mapping for cut-off times (#252)

INT-502

---------

Co-authored-by: Clerise Swart <[email protected]>

apps/sandbox/src/composables/useWeekdays.spec.ts

@@ -0,0 +1,33 @@
+import {nextTick} from 'vue';
+import {afterEach, beforeEach, describe, expect, it, vi} from 'vitest';
+import {createPinia, setActivePinia} from 'pinia';
+
+/**
+ * @vitest-environment happy-dom
+ */
+
+describe('useWeekdays', () => {
+  beforeEach(() => {
+    setActivePinia(createPinia());
+  });
+
+  afterEach(() => {
+    vi.resetModules();
+    vi.restoreAllMocks();
+  });
+
+  it('returns weekdays in English for en-US', async () => {
+    vi.mock('./useLanguage', () => ({
+      useLanguage: vi.fn(() => ({
+        language: {value: {code: 'en-US'}},
+      })),
+    }));
+
+    const {useWeekdays} = await import('./useWeekdays');
+    await nextTick();
+
+    const weekdays = useWeekdays();
+
+    expect(weekdays.value).toEqual(['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']);
+  });
+});

apps/sandbox/src/composables/useWeekdays.ts

@@ -1,13 +1,13 @@
 import {computed, type ComputedRef} from 'vue';
+import {setDay} from 'date-fns';
 import {useLanguage} from './useLanguage';
 
 export const useWeekdays = (): ComputedRef<string[]> => {
   const language = useLanguage();
 
   return computed(() => {
     return Array.from({length: 7}, (_, i) => {
-      const date = new Date(0);
-      date.setDate(i + 5);
+      const date = setDay(new Date(), i, {weekStartsOn: 0});
 
       return date.toLocaleDateString(language.language.value.code, {weekday: 'long'});
     });