Fix toAbsoluteLocaleDate and add more tests (go-gitea#32387)

Author: wxiaoguang

web_src/js/webcomponents/absolute-date.test.ts

@@ -13,9 +13,14 @@ test('toAbsoluteLocaleDate', () => {
     day: 'numeric',
   })).toEqual('15. März 2024');
 
-  expect(toAbsoluteLocaleDate('12345-03-15 01:02:03', '', {
-    year: 'numeric',
-    month: 'short',
-    day: 'numeric',
-  })).toEqual('Mar 15, 12345');
+  // these cases shouldn't happen
+  expect(toAbsoluteLocaleDate('2024-03-15 01:02:03', '', {})).toEqual('Invalid Date');
+  expect(toAbsoluteLocaleDate('10000-01-01', '', {})).toEqual('Invalid Date');
+
+  // test different timezone
+  const oldTZ = process.env.TZ;
+  process.env.TZ = 'America/New_York';
+  expect(new Date('2024-03-15').toLocaleString()).toEqual('3/14/2024, 8:00:00 PM');
+  expect(toAbsoluteLocaleDate('2024-03-15')).toEqual('3/15/2024, 12:00:00 AM');
+  process.env.TZ = oldTZ;
 });

web_src/js/webcomponents/absolute-date.ts

@@ -1,5 +1,12 @@
-export function toAbsoluteLocaleDate(date: string, lang: string, opts: Intl.DateTimeFormatOptions) {
-  return new Date(date).toLocaleString(lang || [], opts);
+export function toAbsoluteLocaleDate(date: string, lang?: string, opts?: Intl.DateTimeFormatOptions) {
+  // only use the date part, it is guaranteed to be in ISO format (YYYY-MM-DDTHH:mm:ss.sssZ) or (YYYY-MM-DD)
+  // if there is an "Invalid Date" error, there must be something wrong in code and should be fixed.
+  // TODO: there is a root problem in backend code: the date "YYYY-MM-DD" is passed to backend without timezone (eg: deadline),
+  // then backend parses it in server's timezone and stores the parsed timestamp into database.
+  // If the user's timezone is different from the server's, the date might be displayed in the wrong day.
+  const dateSep = date.indexOf('T');
+  date = dateSep === -1 ? date : date.substring(0, dateSep);
+  return new Date(`${date}T00:00:00`).toLocaleString(lang || [], opts);
 }
 
 window.customElements.define('absolute-date', class extends HTMLElement {
@@ -15,14 +22,8 @@ window.customElements.define('absolute-date', class extends HTMLElement {
     const lang = this.closest('[lang]')?.getAttribute('lang') ||
       this.ownerDocument.documentElement.getAttribute('lang') || '';
 
-    // only use the date part, it is guaranteed to be in ISO format (YYYY-MM-DDTHH:mm:ss.sssZ)
-    let date = this.getAttribute('date');
-    let dateSep = date.indexOf('T');
-    dateSep = dateSep === -1 ? date.indexOf(' ') : dateSep;
-    date = dateSep === -1 ? date : date.substring(0, dateSep);
-
     if (!this.shadowRoot) this.attachShadow({mode: 'open'});
-    this.shadowRoot.textContent = toAbsoluteLocaleDate(date, lang, opt);
+    this.shadowRoot.textContent = toAbsoluteLocaleDate(this.getAttribute('date'), lang, opt);
   };
 
   attributeChangedCallback(_name, oldValue, newValue) {