Support use of timezones specified in ICS

lib/ical/component.js

@@ -502,5 +502,19 @@ class Component {
       this.jCal, this._designSet
     );
   }
+
+  /**
+   * Returns the highest-level component containing this component. If the
+   * component has no parent, this component will be returned.
+   *
+   * @return {ICAL.Component}
+   */
+  getRootComponent() {
+    if (!this.parent) {
+      return this;
+    }
+
+    return this.parent.getRootComponent();
+  }
 }
 export default Component;

lib/ical/property.js

@@ -404,5 +404,18 @@ class Property {
       this.jCal, this._designSet, true
     );
   }
+
+  /**
+   * Returns the highest-level component containing this property, if any.
+   *
+   * @return {ICAL.Component}
+   */
+  getRootComponent() {
+    if (!this.parent) {
+      return null;
+    }
+
+    return this.parent.getRootComponent();
+  }
 }
 export default Property;

lib/ical/time.js

@@ -165,25 +165,49 @@ class Time {
     }
 
     let zone;
+    let zoneId;
 
     if (aValue[19] && aValue[19] === 'Z') {
-      zone = 'Z';
+      zone = Timezone.utcTimezone;
     } else if (prop) {
-      zone = prop.getParameter('tzid');
+      zoneId = prop.getParameter('tzid');
+
+      if (prop.parent) {
+        if (prop.parent.name === 'standard' || prop.parent.name === 'daylight') {
+          zone = Timezone.floating;
+        } else {
+          const root = prop.getRootComponent();
+
+          const rootZones = root.getAllSubcomponents('vtimezone');
+          for (const rootZone of rootZones) {
+            if (rootZone.getFirstProperty('tzid').getFirstValue() === zoneId) {
+              zone = new Timezone({
+                component: rootZone,
+                tzid: zoneId,
+              });
+
+              break;
+            }
+          }
+        }
+      }
     }
 
-    // 2012-10-10T10:10:10(Z)?
-    let time = new Time({
+    const timeData = {
       year: strictParseInt(aValue.slice(0, 4)),
       month: strictParseInt(aValue.slice(5, 7)),
       day: strictParseInt(aValue.slice(8, 10)),
       hour: strictParseInt(aValue.slice(11, 13)),
       minute: strictParseInt(aValue.slice(14, 16)),
       second: strictParseInt(aValue.slice(17, 19)),
-      timezone: zone
-    });
+    };
+
+    if (zoneId && !zone) {
+      timeData.timezone = zoneId;
+    }
 
-    return time;
+    // 2012-10-10T10:10:10(Z)?
+    return new Time(timeData, zone);
   }
 
   /**

samples/timezone_from_file.ics

@@ -0,0 +1,18 @@
+BEGIN:VCALENDAR
+PRODID:-//Google Inc//Google Calendar 70.9054//EN
+VERSION:2.0
+BEGIN:VTIMEZONE
+TZID:Nowhere/Middle
+BEGIN:STANDARD
+DTSTART:16010101T000000
+TZOFFSETFROM:-0741
+TZOFFSETTO:-0741
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20230306T080000Z
+DTSTART;TZID=Nowhere/Middle:20230306T134200
+DTEND;TZID=Nowhere/Middle:20230306T144200
+SUMMARY:A test event
+END:VEVENT
+END:VCALENDAR

test/parse_test.js

@@ -278,4 +278,28 @@ suite('parserv2', function() {
       assert.deepEqual(unfold(input), expected);
     });
   });
+
+  suite('embedded timezones', function() {
+    let icsDataEmbeddedTimezones;
+    suiteSetup(async function() {
+      icsDataEmbeddedTimezones = await testSupport.loadSample('timezone_from_file.ics');
+    });
+
+    test('used in event date', function() {
+      const parsed = ICAL.parse(icsDataEmbeddedTimezones);
+      const component = new ICAL.Component(parsed);
+
+      const event = new ICAL.Event(component.getFirstSubcomponent('vevent'));
+      const startDate = event.startDate.toJSDate();
+      const endDate = event.endDate.toJSDate();
+
+      assert.equal(startDate.getUTCDate(), 6);
+      assert.equal(startDate.getUTCHours(), 21);
+      assert.equal(startDate.getUTCMinutes(), 23);
+
+      assert.equal(endDate.getUTCDate(), 6);
+      assert.equal(endDate.getUTCHours(), 22);
+      assert.equal(endDate.getUTCMinutes(), 23);
+    });
+  });
 });

test/recur_expansion_test.js

@@ -37,8 +37,8 @@ suite('recur_expansion', function() {
   suite('initialization', function() {
     test('successful', function() {
       assert.deepEqual(
-        new Date(2012, 9, 2, 10),
-        subject.last.toJSDate()
+        subject.last.toJSDate(),
+        new Date('2012-10-02T17:00:00Z')
       );
 
       assert.instanceOf(subject.ruleIterators, Array);
@@ -85,31 +85,31 @@ suite('recur_expansion', function() {
   suite('#_ensureRules', function() {
     test('.ruleDates', function() {
       let expected = [
-        new Date(2012, 10, 5, 10),
-        new Date(2012, 10, 10, 10),
-        new Date(2012, 10, 30, 10)
+        new Date('2012-11-05T18:00:00.000Z'),
+        new Date('2012-11-10T18:00:00.000Z'),
+        new Date('2012-11-30T18:00:00.000Z')
       ];
 
 
       let dates = subject.ruleDates.map(function(time) {
         return time.toJSDate();
       });
 
-      assert.deepEqual(expected, dates);
+      assert.deepEqual(dates, expected);
     });
 
     test('.exDates', function() {
       let expected = [
-        new Date(2012, 11, 4, 10),
-        new Date(2013, 1, 5, 10),
-        new Date(2013, 3, 2, 10)
+        new Date('2012-12-04T18:00:00.000Z'),
+        new Date('2013-02-05T18:00:00.000Z'),
+        new Date('2013-04-02T17:00:00.000Z')
       ];
 
       let dates = subject.exDates.map(function(time) {
         return time.toJSDate();
       });
 
-      assert.deepEqual(expected, dates);
+      assert.deepEqual(dates, expected);
     });
   });
 
@@ -203,12 +203,12 @@ suite('recur_expansion', function() {
     // I use JS dates widely because it is much easier
     // to compare them via chai's deepEquals function
     let expected = [
-      new Date(2012, 9, 2, 10),
-      new Date(2012, 10, 5, 10),
-      new Date(2012, 10, 6, 10),
-      new Date(2012, 10, 10, 10),
-      new Date(2012, 10, 30, 10),
-      new Date(2013, 0, 1, 10)
+      new Date('2012-10-02T17:00:00.000Z'),
+      new Date('2012-11-05T18:00:00.000Z'),
+      new Date('2012-11-06T18:00:00.000Z'),
+      new Date('2012-11-10T18:00:00.000Z'),
+      new Date('2012-11-30T18:00:00.000Z'),
+      new Date('2013-01-01T18:00:00.000Z')
     ];
 
     test('6 items', function() {
@@ -238,11 +238,11 @@ suite('recur_expansion', function() {
 
       let dates = [];
       let expected = [
-        new Date(2012, 9, 2, 10),
-        new Date(2012, 10, 5, 10),
-        new Date(2012, 10, 6, 10),
-        new Date(2012, 10, 10, 10),
-        new Date(2012, 11, 4, 10)
+        new Date('2012-10-02T17:00:00.000Z'),
+        new Date('2012-11-05T18:00:00.000Z'),
+        new Date('2012-11-06T18:00:00.000Z'),
+        new Date('2012-11-10T18:00:00.000Z'),
+        new Date('2012-12-04T18:00:00.000Z')
       ];
 
       while (inc++ < max && (next = subject.next())) {
@@ -263,6 +263,11 @@ suite('recur_expansion', function() {
 
 
   suite('#toJSON', function() {
+    // While other tests in this file don't require specifying a timezone, we
+    // need to do so here because we're building the `RecurExpansion` from a
+    // limited subset of the ICS which does not include the timezone definition.
+    testSupport.useTimezones('America/Los_Angeles');
+
     test('from start', function() {
       let json = subject.toJSON();
       let newIter = new ICAL.RecurExpansion(json);