Update and Map Deprecated Timezone

.changeset/light-students-learn.md

@@ -0,0 +1,5 @@
+---
+'@shopify/dates': patch
+---
+
+Correctly support deprecated timezones in older browsers when calling `formatDate()`. For example, modern browsers support both `Europe/Kyiv` and (the now deprecated) `Europe/Kiev`, but browsers as recent as Chrome 131 on MacOS only support `Europe/Kiev`. Note: This is a purely internal change which should not effect the result of calling `formatDate()`.

packages/dates/src/deprecated-timezones.ts

@@ -28,6 +28,7 @@ export const deprecatedTimezones: {[key: string]: string} = {
   'Canada/Yukon': 'America/Whitehorse',
   'Chile/Continental': 'America/Santiago',
   'Chile/EasterIsland': 'Pacific/Easter',
+  'Europe/Kyiv': 'Europe/Kiev',
   Cuba: 'America/Havana',
   Egypt: 'Africa/Cairo',
   Eire: 'Europe/Dublin',

packages/dates/src/utilities/formatDate.ts

@@ -1,3 +1,5 @@
+import {mapDeprecatedTimezones} from '../map-deprecated-timezones';
+
 const intl = new Map<string, Intl.DateTimeFormat>();
 export function memoizedGetDateTimeFormat(
   locales?: string | string[],
@@ -58,7 +60,12 @@ export function formatDate(
     }).format(adjustedDate);
   }
 
-  return memoizedGetDateTimeFormat(locales, options).format(date);
+  return memoizedGetDateTimeFormat(locales, {
+    ...options,
+    timeZone: options.timeZone
+      ? mapDeprecatedTimezones(options.timeZone)
+      : undefined,
+  }).format(date);
 }
 
 export function dateTimeFormatCacheKey(

packages/dates/src/utilities/tests/formatDate.test.ts

@@ -0,0 +1,22 @@
+import {formatDate} from '../formatDate';
+
+jest.mock('../../map-deprecated-timezones', () => ({
+  mapDeprecatedTimezones: jest.fn(),
+}));
+
+const mapDeprecatedTimezones: jest.Mock = jest.requireMock(
+  '../../map-deprecated-timezones',
+).mapDeprecatedTimezones;
+
+describe('formatDate', () => {
+  it('maps the deprecated timezone', () => {
+    const date = new Date();
+    const locale = 'en-UA';
+    const options: Intl.DateTimeFormatOptions = {
+      timeZone: 'Europe/Kyiv',
+    };
+
+    formatDate(date, locale, options);
+    expect(mapDeprecatedTimezones).toHaveBeenCalledWith('Europe/Kyiv');
+  });
+});