Add optional "timezone" parameter to date helper

ChangeLog.md

@@ -4,7 +4,8 @@ Handlebars for XP web frontends change log
 ## ?.?.? / ????-??-??
 
 * Implemented basic timezone handling by passing default timezone to
-  the `web.frontend.helpers.Dates` helpers extension.
+  the `web.frontend.helpers.Dates` helpers extension, overwriteable by
+  passing e.g. `timezone="America/New_York"` in the handlebars helper.
   (@thekid)
 * Merged PR #4: Make template engine extensible; and extract the hard
   wired date formatting to its own extension

README.md

@@ -80,6 +80,7 @@ The `date` helper accepts anything the `util.Date` class accepts as constructor
 {{date created}}
 {{date created format="d.m.Y"}}
 {{date created format="us:short"}}
+{{date created timezone="America/New_York"}}
 ```
 
 ### Logging

src/main/php/web/frontend/helpers/Dates.class.php

@@ -23,14 +23,15 @@ public function helpers() {
     yield 'date' => function($in, $context, $options) {
       static $resolution= ['s' => 1, 'ms' => 1000];
 
+      $tz= isset($options['timezone']) ? TimeZone::getByName($options['timezone']) : $this->timezone;
       if (!isset($options[0])) {
-        $d= Date::now($this->timezone);
+        $d= Date::now($tz);
       } else if ($options[0] instanceof Date) {
-        $d= $this->timezone->translate($options[0]);
+        $d= $tz->translate($options[0]);
       } else if ($r= $options['timestamp'] ?? null) {
-        $d= new Date('@'.(int)($options[0] / $resolution[$r]), $this->timezone);
+        $d= new Date('@'.(int)($options[0] / $resolution[$r]), $tz);
       } else {
-        $d= $this->timezone->translate(new Date($options[0]));
+        $d= $tz->translate(new Date($options[0]));
       }
 
       return $d->toString($this->formats[$options['format'] ?? null] ?? $options['format']);

src/test/php/web/frontend/unittest/DatesTest.class.php

@@ -12,15 +12,16 @@ class DatesTest extends HandlebarsTest {
   protected function extensions() {
     return [new Dates(new TimeZone(self::TZ), [
       null       => self::FORMAT,
-      'us:short' => 'Y-m-d',
+      'us:short' => 'm/d/Y',
     ])];
   }
 
   /** @return iterable */
   private function dates() {
-    yield new Date('2021-02-13');
-    yield '13.02.2021';
-    yield 1613209181;
+    yield new Date('2021-02-13 22:30:00', new TimeZone(self::TZ));
+    yield new Date('13.02.2021 12:30:00+01:00');
+    yield '2021-02-13T11:30:00Z';
+    yield 1613215800;
   }
 
   #[Test, Values('dates')]
@@ -34,7 +35,7 @@ public function dates_with_format($date) {
   #[Test, Values('dates')]
   public function dates_with_named_format($date) {
     Assert::equals(
-      '2021-02-13',
+      '02/13/2021',
       $this->transform('{{date tested format="us:short"}}', ['tested' => $date])
     );
   }
@@ -57,11 +58,19 @@ public function timestamp_resolution($template) {
     Assert::equals('13.02.2021', $this->transform($template));
   }
 
-  #[Test, Values(eval: '[new Date("13.02.2021 11:30:00", new TimeZone("UTC")), "13.02.2021 11:30:00 UTC", 1613215800]')]
-  public function converted_to_supplied_timezone($date) {
+  #[Test, Values('dates')]
+  public function converted_to_default_timezone($date) {
     Assert::equals(
       '13.02.2021 22:30:00',
       $this->transform('{{date tested format="d.m.Y H:i:s"}}', ['tested' => $date])
     );
   }
+
+  #[Test, Values('dates')]
+  public function converted_to_supplied_timezone($date) {
+    Assert::equals(
+      '13.02.2021 06:30:00',
+      $this->transform('{{date tested format="d.m.Y H:i:s" timezone="America/New_York"}}', ['tested' => $date])
+    );
+  }
 }