fix: preserveTimezones support for RFC2822 date, #784

Author: harttle

src/util/liquid-date.ts

@@ -3,7 +3,11 @@ import { isString } from './underscore'
 
 // one minute in milliseconds
 const OneMinute = 60000
-const ISO8601_TIMEZONE_PATTERN = /([zZ]|([+-])(\d{2}):(\d{2}))$/
+/**
+ * Need support both ISO8601 and RFC2822 as in major browsers & NodeJS
+ * RFC2822: https://datatracker.ietf.org/doc/html/rfc2822#section-3.3
+ */
+const TIMEZONE_PATTERN = /([zZ]|([+-])(\d{2}):?(\d{2}))$/
 const monthNames = [
   'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August',
   'September', 'October', 'November', 'December'
@@ -126,7 +130,7 @@ export class LiquidDate {
    * Given that a template is expected to be parsed fewer times than rendered.
    */
   static createDateFixedToTimezone (dateString: string, locale: string): LiquidDate {
-    const m = dateString.match(ISO8601_TIMEZONE_PATTERN)
+    const m = dateString.match(TIMEZONE_PATTERN)
     // representing a UTC timestamp
     if (m && m[1] === 'Z') {
       return new LiquidDate(+new Date(dateString), locale, 0)

test/integration/filters/date.spec.ts

@@ -80,19 +80,23 @@ describe('filters/date', function () {
     return test('{{ "1991-02-22T00:00:00" | date: "%Y-%m-%dT%H:%M:%S"}}', '1991-02-22T00:00:00')
   })
   describe('when preserveTimezones is enabled', function () {
-    const opts: LiquidOptions = { preserveTimezones: true }
+    const opts: LiquidOptions = { preserveTimezones: true, locale: 'en-US' }
 
     it('should not change the timezone between input and output', function () {
       return test('{{ "1990-12-31T23:00:00Z" | date: "%Y-%m-%dT%H:%M:%S"}}', '1990-12-31T23:00:00', undefined, opts)
     })
     it('should apply numeric timezone offset (0)', function () {
-      return test('{{ "1990-12-31T23:00:00+00:00" | date: "%Y-%m-%dT%H:%M:%S"}}', '1990-12-31T23:00:00', undefined, opts)
+      return test('{{ "1990-12-31T23:00:00+00:00" | date: "%Y-%m-%dT%H:%M:%S %z"}}', '1990-12-31T23:00:00 +0000', undefined, opts)
     })
     it('should apply numeric timezone offset (-1)', function () {
-      return test('{{ "1990-12-31T23:00:00-01:00" | date: "%Y-%m-%dT%H:%M:%S"}}', '1990-12-31T23:00:00', undefined, opts)
+      return test('{{ "1990-12-31T23:00:00-01:00" | date: "%Y-%m-%dT%H:%M:%S %z"}}', '1990-12-31T23:00:00 -0100', undefined, opts)
     })
     it('should apply numeric timezone offset (+2.30)', function () {
-      return test('{{ "1990-12-31T23:00:00+02:30" | date: "%Y-%m-%dT%H:%M:%S"}}', '1990-12-31T23:00:00', undefined, opts)
+      return test('{{ "1990-12-31T23:00:00+02:30" | date: "%Y-%m-%dT%H:%M:%S %z"}}', '1990-12-31T23:00:00 +0230', undefined, opts)
+    })
+    it('should support timezone in more casual JavaScript Date', async () => {
+      await test('{{ "2025-01-02 03:04:05 -0100" | date: "%Y-%m-%dT%H:%M:%S %z" }}', '2025-01-02T03:04:05 -0100', undefined, opts)
+      await test('{{ "2025-01-02 03:04:05 -0100" | date }}', 'Thursday, January 2, 2025 at 3:04 am -0100', undefined, opts)
     })
     it('should automatically work when timezone not specified', function () {
       return test('{{ "1990-12-31T23:00:00" | date: "%Y-%m-%dT%H:%M:%S"}}', '1990-12-31T23:00:00', undefined, opts)