fix(HH-590): define realtime timestamp range (#151)

Co-authored-by: Rogee <rogee@ipao.vip>

frontend/app/javascript/shared/helpers/specs/timeHelper.spec.js

@@ -6,6 +6,7 @@ import {
   shortTimestamp,
   getDayDifferenceFromNow,
   hasOneDayPassed,
+  isNewerTimestamp,
 } from 'shared/helpers/timeHelper';
 import { zhCN } from 'date-fns/locale';
 
@@ -20,6 +21,25 @@ afterEach(() => {
   vi.useRealTimers();
 });
 
+describe('#isNewerTimestamp', () => {
+  it.each([
+    ['Unix seconds', 1_700_000_000, 1_700_000_001],
+    ['numeric strings', '1700000000', '1700000001'],
+    ['early Unix milliseconds', 978_307_200_000, 1_700_000_000],
+    ['below the former 1e12 threshold', 999_999_999_999, 1_000_000_000_000],
+  ])('orders %s', (_label, current, next) => {
+    expect(isNewerTimestamp(current, next)).toBe(true);
+  });
+
+  it('preserves missing and invalid timestamp compatibility', () => {
+    expect(isNewerTimestamp(null, 'invalid')).toBe(true);
+    expect(isNewerTimestamp(1_700_000_000, null)).toBe(true);
+    expect(isNewerTimestamp('invalid', 1_700_000_000)).toBe(true);
+    expect(isNewerTimestamp(1_700_000_000, 'invalid')).toBe(false);
+    expect(isNewerTimestamp(1_700_000_000, 9e15)).toBe(false);
+  });
+});
+
 describe('#messageStamp', () => {
   it('returns correct value', () => {
     expect(messageStamp(1612971343)).toEqual('3:35 PM');