browser-side momentjs: use guess for unknown timezones (#188899)

## Summary Fix #123579
elastic · Jul 24, 2024 · 69268b8 · 69268b8
1 parent db6886f
commit 69268b8
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Showing 3 changed files with 23 additions and 8 deletions.
diff --git a/...e/integrations/core-integrations-browser-internal/src/moment/moment_service.test.mocks.ts b/...e/integrations/core-integrations-browser-internal/src/moment/moment_service.test.mocks.ts
@@ -10,6 +10,7 @@ export const momentMock = {
   locale: jest.fn(() => 'default-locale'),
   tz: {
     setDefault: jest.fn(),
+    guess: jest.fn(),
     zone: jest.fn(
       (z) => [{ name: 'tz1' }, { name: 'tz2' }, { name: 'tz3' }].find((f) => z === f.name) || null
     ),

diff --git a/...es/core/integrations/core-integrations-browser-internal/src/moment/moment_service.test.ts b/...es/core/integrations/core-integrations-browser-internal/src/moment/moment_service.test.ts
@@ -7,18 +7,22 @@
  */
 
 import { momentMock } from './moment_service.test.mocks';
+
+import { BehaviorSubject } from 'rxjs';
 import { MomentService } from './moment_service';
 import { uiSettingsServiceMock } from '@kbn/core-ui-settings-browser-mocks';
-import { BehaviorSubject } from 'rxjs';
 
 describe('MomentService', () => {
   let service: MomentService;
+
   beforeEach(() => {
     momentMock.tz.setDefault.mockClear();
+    momentMock.tz.guess.mockClear();
     momentMock.weekdays.mockClear();
     momentMock.updateLocale.mockClear();
     service = new MomentService();
   });
+
   afterEach(() => service.stop());
 
   const flushPromises = () => new Promise((resolve) => setTimeout(resolve, 100));
@@ -36,24 +40,30 @@ describe('MomentService', () => {
     expect(momentMock.updateLocale).toHaveBeenCalledWith('default-locale', { week: { dow: 0 } });
   });
 
-  it('does not set unknkown zone', async () => {
-    const tz$ = new BehaviorSubject('timezone/undefined');
+  it('sets timezone when a zone is defined', async () => {
+    const tz$ = new BehaviorSubject('tz3');
     const uiSettings = uiSettingsServiceMock.createSetupContract();
     uiSettings.get$.mockReturnValueOnce(tz$);
 
     service.start({ uiSettings });
     await flushPromises();
-    expect(momentMock.tz.setDefault).not.toHaveBeenCalled();
+    expect(momentMock.tz.setDefault).toHaveBeenCalledWith('tz3');
   });
 
-  it('sets timezone when a zone is defined', async () => {
-    const tz$ = new BehaviorSubject('tz3');
+  it('set timezone with result of moment.tz.guess for unknown zone', async () => {
+    const tz$ = new BehaviorSubject('timezone/undefined');
     const uiSettings = uiSettingsServiceMock.createSetupContract();
     uiSettings.get$.mockReturnValueOnce(tz$);
 
+    const guessedTz = { guessed: true };
+    momentMock.tz.guess.mockReturnValue(guessedTz);
+
     service.start({ uiSettings });
     await flushPromises();
-    expect(momentMock.tz.setDefault).toHaveBeenCalledWith('tz3');
+
+    expect(momentMock.tz.guess).toHaveBeenCalledTimes(1);
+    expect(momentMock.tz.setDefault).toHaveBeenCalledTimes(1);
+    expect(momentMock.tz.setDefault).toHaveBeenCalledWith(guessedTz);
   });
 
   test('updates moment config', async () => {

diff --git a/packages/core/integrations/core-integrations-browser-internal/src/moment/moment_service.ts b/packages/core/integrations/core-integrations-browser-internal/src/moment/moment_service.ts
@@ -26,7 +26,11 @@ export class MomentService implements CoreService {
   public async start({ uiSettings }: StartDeps) {
     const setDefaultTimezone = (tz: string) => {
       const zone = moment.tz.zone(tz);
-      if (zone) moment.tz.setDefault(zone.name);
+      if (zone) {
+        moment.tz.setDefault(zone.name);
+      } else {
+        moment.tz.setDefault(moment.tz.guess());
+      }
     };
     const setStartDayOfWeek = (day: string) => {
       const dow = moment.weekdays().indexOf(day);