fix: getToday() uses the correct initial date

getToday.js

@@ -1,6 +1,5 @@
 import getTimezoneOffset from 'date-fns-tz/getTimezoneOffset'
 import addMilliseconds from 'date-fns/addMilliseconds'
-import addMinutes from 'date-fns/addMinutes'
 
 /**
  * Get the Date of 0:00 today in the given timezone
@@ -13,9 +12,8 @@ export default function getToday (timezone = undefined, now = undefined) {
   if (now !== undefined && !(now instanceof Date)) {
     throw new Error('The 2nd argument must be undefined or an instance of date.')
   }
-  // Step 1: Undo system timezone for new Date() (system -> UTC)
-  const inSystem = new Date()
-  const inUTC = now || addMinutes(inSystem, -inSystem.getTimezoneOffset())
+  // Step 1: Determine now (new Date() carries no timezone info, always in UTC)
+  const inUTC = now || new Date()
 
   // Step 2: Apply target timezone (UTC -> zoned)
   const tzOffset = timezone ? getTimezoneOffset(timezone, inUTC) : 0

tests/getToday.test.js

@@ -26,6 +26,10 @@ describe('applyDate', () => {
     // Tue Oct 03 2023 01:30:00 GMT+0000 (UTC)
     const today2 = getToday(tz, new Date('2023-10-03T01:30:00.000Z'))
     expect(today2.toISOString()).to.equal('2023-10-03T00:00:00.000Z')
+
+    // Tue Apr 16 2024 15:01:22 GMT+0000 (UTC)
+    const today3 = getToday(tz, new Date('2024-04-16T15:01:22.871Z'))
+    expect(today3.toISOString()).to.equal('2024-04-16T00:00:00.000Z')
   })
 
   test('Europe/Berlin', () => {

tests/isSameDay.test.js

@@ -49,4 +49,10 @@ describe('isSameDay', () => {
     const date2 = new Date('2024-04-11T00:00:00Z')
     expect(isSameDay(date1, date2, 'UTC')).to.be.false
   })
+
+  test('AUS Date Picker bug', () => {
+    const date1 = new Date('2024-04-16T14:30:00.000Z')
+    const date2 = new Date('2024-04-16T00:00:00.000Z')
+    expect(isSameDay(date1, date2, 'UTC')).to.be.true
+  })
 })