✨ Temporal and DST fix

action.yml

@@ -11,6 +11,9 @@ inputs:
   schedules:
     description: 'An array of strings representing the meeting schedules in the format YYYY-MM-DD (ISO-8601 intervals).'
     required: true
+  timezone:
+    description: 'Timezone to use for schedule times (e.g. "America/Chicago", "Europe/Madrid"). Useful for following daylight saving time (DST) / summer time. Default: "UTC"'
+    required: false
   createWithin:
     description: 'Defines when the meeting issues are created using ISO-8601 durations. Defaults to one week before the meeting (Using the ISO-8601 durations format, this is P7D).'
     default: 'P7D'

lib/meetings.js

@@ -23,7 +23,7 @@ module.exports.setMeetingIssueBody = async function (client, opts) {
 
 function getNextIssue (opts) {
   const now = opts.now || Temporal.Now.instant()
-  const date = getNextScheduledMeeting(opts.schedules, now)
+  const date = getNextScheduledMeeting(opts.schedules, now, opts.timezone)
   const title = typeof opts.issueTitle === 'function' ? opts.issueTitle({ date }) : opts.issueTitle
 
   const issue = {
@@ -76,18 +76,33 @@ const shouldCreateNextMeetingIssue = module.exports.shouldCreateNextMeetingIssue
   return issue
 }
 
-const getNextScheduledMeeting = module.exports.getNextScheduledMeeting = function (schedules = [], now = Temporal.Now.instant()) {
+const getNextScheduledMeeting = module.exports.getNextScheduledMeeting = function (schedules = [], now = Temporal.Now.instant(), timezone) {
   return schedules
     .map((s = `${now}/P7D`) => {
       // Parse interval
       const [startStr, durationStr] = s.split('/')
-      const start = Temporal.Instant.from(startStr)
       const duration = Temporal.Duration.from(durationStr)
+      let next
+
+      if (timezone) {
+        // parse as local in specified tz
+        try {
+          const zonedStart = Temporal.ZonedDateTime.from(`${startStr}[${timezone}]`)
+          next = zonedStart.toInstant()
+        } catch (e) {
+          console.warn(`invalid timezone '${timezone}'; using UTC`)
+          console.error(e) // s/b caused by invalid timezone but log error just in case for troubleshooting
+        }
+      }
+
+      if (!next) {
+        // parse as UTC
+        next = Temporal.Instant.from(startStr)
+      }
 
       // Get datetime for next event after now
-      let next = start
       while (next.epochMilliseconds <= now.epochMilliseconds) {
-        const zonedNext = next.toZonedDateTimeISO('UTC')
+        const zonedNext = next.toZonedDateTimeISO(timezone || 'UTC')
         next = zonedNext.add(duration).toInstant()
       }
 

run.js

@@ -20,6 +20,7 @@ const pkg = require('./package.json')
     // variables we use for timing
     const schedules = list(core.getInput('schedules'))
     const createWithin = core.getInput('createWithin')
+    const timezone = core.getInput('timezone')
 
     // variables we use for labels
     const agendaLabel = core.getInput('agendaLabel')
@@ -115,6 +116,7 @@ const pkg = require('./package.json')
     const opts = {
       ...repo,
       schedules,
+      timezone,
       meetingLabels,
       createWithin,
       agendaLabel,

test/index.js

@@ -131,6 +131,71 @@ suite(`${pkg.name} unit`, () => {
     assert(formattedDate.includes('Mar'))
     assert(formattedDate.includes('08:00 AM'))
   })
+
+  test('schedule parsing with timezone - UTC default', () => {
+    const schedules = ['2024-03-27T21:00:00.0Z/P2W']
+    const now = Temporal.Instant.from('2024-03-20T13:00:00.0Z')
+    const next = meetings.getNextScheduledMeeting(schedules, now)
+    const expected = Temporal.Instant.from('2024-03-27T21:00:00.0Z')
+    assert.strictEqual(next.epochMilliseconds, expected.epochMilliseconds)
+  })
+
+  test('schedule parsing with timezone - Chicago', () => {
+    const schedules = ['2024-03-27T21:00:00.0/P2W']
+    const now = Temporal.Instant.from('2024-03-20T13:00:00.0Z')
+    const next = meetings.getNextScheduledMeeting(schedules, now, 'America/Chicago')
+    // 21:00 CDT == 02:00 UTC next day
+    const expected = Temporal.Instant.from('2024-03-28T02:00:00.0Z')
+    assert.strictEqual(next.epochMilliseconds, expected.epochMilliseconds)
+  })
+
+  test('schedule parsing with timezone - DST spring forward', () => {
+    const schedules = ['2025-03-09T01:00:00.0/P2W']
+
+    const beforeSpring = Temporal.Instant.from('2025-03-08T13:00:00.0Z')
+    const nextBefore = meetings.getNextScheduledMeeting(schedules, beforeSpring, 'America/Chicago')
+    // 01:00 CST == 07:00 UTC (before spring forward)
+    const expectedBefore = Temporal.Instant.from('2025-03-09T07:00:00.0Z')
+    assert.strictEqual(nextBefore.epochMilliseconds, expectedBefore.epochMilliseconds)
+
+    const afterSpring = Temporal.Instant.from('2025-03-09T13:00:00.0Z')
+    const nextAfter = meetings.getNextScheduledMeeting(schedules, afterSpring, 'America/Chicago')
+    // 01:00 CDT == 06:00 UTC (after spring forward)
+    const expectedAfter = Temporal.Instant.from('2025-03-23T06:00:00.0Z')
+    assert.strictEqual(nextAfter.epochMilliseconds, expectedAfter.epochMilliseconds)
+  })
+
+  test('schedule parsing with timezone - DST fall back', () => {
+    const schedules = ['2025-11-02T01:00:00.0/P2W']
+
+    const beforeFallBack = Temporal.Instant.from('2025-11-01T13:00:00.0Z')
+    const nextBefore = meetings.getNextScheduledMeeting(schedules, beforeFallBack, 'America/Chicago')
+    // 01:00 CDT == 06:00 UTC (before fall back)
+    const expectedBefore = Temporal.Instant.from('2025-11-02T06:00:00.0Z')
+    assert.strictEqual(nextBefore.epochMilliseconds, expectedBefore.epochMilliseconds)
+
+    const afterFallBack = Temporal.Instant.from('2025-11-02T13:00:00.0Z')
+    const nextAfter = meetings.getNextScheduledMeeting(schedules, afterFallBack, 'America/Chicago')
+    // 01:00 CST == 07:00 UTC (after fall back)
+    const expectedAfter = Temporal.Instant.from('2025-11-16T07:00:00.0Z')
+    assert.strictEqual(nextAfter.epochMilliseconds, expectedAfter.epochMilliseconds)
+  })
+
+  test('schedule parsing with timezone - Los Angeles PST', () => {
+    const schedules = ['2020-04-02T17:00:00/P7D']
+    const now = Temporal.Instant.from('2021-01-01T00:00:00.0Z')
+    const next = meetings.getNextScheduledMeeting(schedules, now, 'America/Los_Angeles')
+    const expected = Temporal.Instant.from('2020-12-31T17:00:00.0-08:00')
+    assert.strictEqual(next.epochMilliseconds, expected.epochMilliseconds)
+  })
+
+  test('schedule parsing with timezone - Los Angeles PDT', () => {
+    const schedules = ['2020-04-02T17:00:00/P7D']
+    const now = Temporal.Instant.from('2021-04-01T00:00:00.0Z')
+    const next = meetings.getNextScheduledMeeting(schedules, now, 'America/Los_Angeles')
+    const expected = Temporal.Instant.from('2021-04-01T17:00:00.0-07:00')
+    assert.strictEqual(next.epochMilliseconds, expected.epochMilliseconds)
+  })
 })
 
 test('shorthands transform', async () => {